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研究者情報

マスター

アカウント（マスター）

  • 氏名

    佐藤　努(サトウ　ツトム), サトウ　ツトム

所属（マスター）

  • 工学研究院　環境循環システム部門　資源循環工学分野

所属（マスター）

  • 工学研究院　環境循環システム部門　資源循環工学分野

独自項目

syllabus

  • 2021, 環境プロセス鉱物学, Environmental and Process Mineralogy, 修士課程, 工学院, 地球化学モデリング、鉱物特性、表面反応、鉱物―水相互作用、汚染浄化
  • 2021, 環境プロセス鉱物学特論, Environmental and Process Mineralogy, 修士課程, 工学院, 地球化学モデリング、鉱物特性、表面反応、鉱物―水相互作用、汚染浄化
  • 2021, 環境地質学Ⅰ, Environmental Geology I, 修士課程, 工学院
  • 2021, 環境地質学特論Ⅰ, Environmental Geology I, 修士課程, 工学院
  • 2021, 環境プロセス鉱物学特論, Environmental and Process Mineralogy, 博士後期課程, 工学院, 地球化学モデリング、鉱物特性、表面反応、鉱物―水相互作用、汚染浄化
  • 2021, 環境地質学特論Ⅰ, Environmental Geology I, 博士後期課程, 工学院
  • 2021, 資源循環システム実験Ⅲ, Experiments for Sustainable Resources Engineering Ⅲ, 学士課程, 工学部, 構造解析，物性評価，鉱物の利用，流体の分析，選別技術
  • 2021, 地球科学, Earth Science, 学士課程, 工学部, 地球システム　地質年代　岩石　鉱物　日本列島の誕生　進化
  • 2021, 資源循環システム実験Ⅱ, Experiments for Sustainable Resources Engineering Ⅱ, 学士課程, 工学部, Ｘ線回折，岩石の構造，岩石の工学的性質，鉱物，地質図，地質巡検，偏光顕微鏡
  • 2021, 資源工学概論, Introduction to Mineral Resources Engineering, 学士課程, 工学部, 鉱物資源　鉱床　探査・開発技術　環境問題　未利用資源　リサイクル

researchmap

プロフィール情報

学位

  • 博士(工学)（早稲田大学）

プロフィール情報

  • 姓

    佐藤, サトウ

  • 名

    努, ツトム

  • ID各種

    200901091654442995

対象リソース

業績リスト

研究キーワード

  • 粘土鉱物   鉱物   多環芳香族炭化水素   イオン交換   岩石-水相互作用   分子進化工学   触媒   アミノ酸   風化   蛇紋岩   変質   超塩基性岩   PAH   越境汚染   環日本海   蛇紋岩化作用   マグネシウム炭酸塩鉱物   ペプチド   資源開発工学   エアロゾル   高アルカリ   黄砂   オマーン   ハイドロタルサイト   メラノイジン   日本海   生物生態工学   環境技術   吸着   透水性   廃棄物工学   環境鉱物学   地球化学   Environmental MineralogyGeochemistryWaste Engineering   

研究分野

  • エネルギー / 地球資源工学、エネルギー学
  • 自然科学一般 / 固体地球科学
  • 自然科学一般 / 宇宙惑星科学

経歴

  • 2011年04月 - 現在 北海道大学工学研究院 教授
  • 2002年 - 2006年 金沢大学自然計測応用研究センター 助教授
  • 2002年 - 2006年 Associate Professor,Division of Earth Dynamics, Institute of Nature and Environmental Technology, Kanazawa University
  • 2006年 - 北海道大学大学院工学研究科 助教授
  • 2006年 - Associate Professor,Graduate School of Engineering, Hokkaido University
  • 1999年 - 2002年 金沢大学大学院自然科学研究科 助教授
  • 1999年 - 2002年 Associate Professor,Division of of Global Environmental Science and Engineering, Graduate School of Natural Science and Technology, Kanazawa University
  • 1999年 金沢大学理学部地球学科 助教授
  • 1999年 Associate Professor,Associate Professor, Department of Earth Science, Faculty of Science, Kanazawa University
  • 1992年 - 1998年 日本原子力研究所 研究員
  • 1992年 - 1998年 Researcher,Japan Atomic Energy Reseach Institute

学歴

  •         - 1992年   早稲田大学   理工学研究科   資源及び材料工学専攻
  •         - 1992年   早稲田大学

委員歴

  • 2018年09月 - 現在   日本粘土学会   理事・常務委員長
  • 2004年 - 2008年   日本原子力学会   編集委員   日本原子力学会
  • 2005年   国際鉱物学連合   環境鉱物学ワーキンググループ 副議長   国際鉱物学連合
  • 2004年   日本鉱物科学学会   英文誌編集委員   日本鉱物科学学会
  • 2000年   日本鉱物科学学会   行事委員   日本鉱物科学学会
  • 1997年   日本粘土学会   常務委員   日本粘土学会

受賞

  • 2022年09月 日本粘土学会 論文賞
  • 2022年06月 資源地質学会 The Best Article Award
  • 2016年09月 日本粘土学会 学会賞
     
    受賞者: 佐藤 努
  • 2015年09月 日本粘土学会 論文賞
     
    受賞者: 佐藤 努
  • 2014年09月 日本粘土学会 論文賞
     
    受賞者: 佐藤 努
  • 2010年09月 資源・素材学会 論文賞
     
    受賞者: 佐藤 努
  • 2010年09月 日本粘土学会 論文賞
     
    受賞者: 佐藤 努
  • 2006年08月 日本鉱物学会 応用鉱物学賞
     
    受賞者: 佐藤 努
  • 2005年 UK-Japan Collaboration Awards-Green Sustainable Chemistry
  • 2004年09月 日本粘土学会 論文賞
     
    受賞者: 佐藤 努
  • 1992年09月 日本粘土学会 奨励賞
     
    受賞者: 佐藤 努

論文

  • Pramesti Prihutami, Raudhatul Islam Chaerun, Yusuke Ohya, Tsubasa Otake, Ryosuke Kikuchi, Tsutomu Sato
    Minerals 14 3 311 - 311 2024年03月15日 
    Previous studies of cadmium and mercury immobilization in geopolymers have produced inconsistent results due to their different pozzolans, metal concentrations, and mixing procedures. Understanding the effects of these parameters on heavy metal immobilization is key to predicting their long-term stability. In this study, cadmium and mercury were incorporated into a metakaolin-based K-activated geopolymer by three mixing procedures and concentrations of 0.02–1.00 wt.%. The samples were then immersed in water for 90 d to determine their stability. The results show that mercury is readily leached from the geopolymer, but cadmium is retained. Adding the heavy metals in salt form converts the metals into cadmium hydroxide and mercury oxide that reside at the bottom of the geopolymer. Mixing the salts with water forms soluble heavy metals prior to geopolymerization. This procedure produces more-homogeneous geopolymers. Cadmium is associated with silicate and aluminate, giving a better stability, whereas mercury forms mercury oxide. Different cadmium and mercury concentrations do not change the metal speciation as mercury is affected by relativistic contribution.
  • Walubita Mufalo, Takahiko Arima, Toshifumi Igarashi, Mayumi Ito, Tsutomu Sato, Shingo Tomiyama, Imasiku Nyambe, Carlito Baltazar Tabelin, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    Environmental Geochemistry and Health 46 2 2024年02月06日
  • Takahiko ARIMA, Kenta NOTO, Walubita MUFALO, Toshifumi IGARASHI, Mayumi ITO, Tsutomu SATO, Hokuto NAKATA, Shouta NAKAYAMA, Mayumi ISHIZUKA
    Resources Processing 70 3 141 - 150 2024年
  • Xiaobo Niu, Yogarajah Elakneswaran, Raudhatul Islam Chaerun, Chuwei Fang, Naoki Hiroyoshi, John L. Provis, Tsutomu Sato
    Separation and Purification Technology 324 124530 - 124530 2023年11月
  • Walubita Mufalo, Pawit Tangviroon, Takahiko Arima, Toshifumi Igarashi, Mayumi Ito, Tsutomu Sato, Kenta Noto, Takeshi Kawashima, Imasiku Nyambe, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    Journal of Geochemical Exploration 249 107209 - 107209 2023年06月
  • Frances Chikanda, Sereyroith Tum, Tatsuya Matsui, Susumu Norota, Tsubasa Otake, Tsutomu Sato
    Resource Geology 73 1 2023年01月
  • Yuto Nishiki, Jordi Cama, Tsubasa Otake, Ryosuke Kikuchi, Misato Shimbashi, Tsutomu Sato
    Applied Geochemistry 148 105544 - 105544 2023年01月
  • Ryohei Kawakita, Akito Saito, Hiroshi Sakuma, Sohtaro Anraku, Ryosuke Kikuchi, Tsubasa Otake, Tsutomu Sato
    Applied Clay Science 231 106722 - 106722 2023年01月
  • Raudhatul Islam Chaerun, Natatsawas Soonthornwiphat, Kanako Toda, Kazuma Kuroda, Xiaobo Niu, Ryosuke Kikuchi, Tsubasa Otake, Yogarajah Elakneswaran, John L. Provis, Tsutomu Sato
    Journal of Hazardous Materials 440 129732 - 129732 2022年10月 [査読有り]
  • Kanako Toda, Daisuke Minato, Takumi Saito, Ryosuke Kikuchi, Tsubasa Otake, Tsutomu Sato
    Cement 9 100042 - 100042 2022年09月 [査読有り][通常論文]
  • Ryosuke Kikuchi, Tsutomu Sato, Naoki Fujii, Misato Shimbashi, Carlo A. Arcilla
    Scientific Reports 12 16012  2022年09月 [査読有り][通常論文]
  • Misato Shimbashi, Shingo Yokoyama, Ryosuke Kikuchi, Tsubasa Otake, Tsutomu Sato
    Clays and Clay Minerals 2022年08月23日 [査読有り]
  • Xiaobo Niu, Yogarajah Elakneswaran, Chaerun Raudhatul Islam, John L. Provis, Tsutomu Sato
    Journal of Hazardous Materials 429 128373 - 128373 2022年05月
  • Shinsaku Nakamura, Toshifumi Igarashi, Yoshitaka Uchida, Mayumi Ito, Kazuyo Hirose, Tsutomu Sato, Walubita Mufalo, Meki Chirwa, Imasiku Nyambe, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    Minerals 12 5 2022年05月 [査読有り]
     
    Effects of the water content of ground surface on windborne lead (Pb) dispersion from the zinc (Zn) leach residue site at the Kabwe mine, Zambia, were simulated. The Pb-bearing Zn plant leach residue site was selected as the source of the dispersion, and water conditions of the surface of the source were evaluated by the modified normalized difference water index (MNDWI) under the actual weather conditions in the year 2019. The MNDWI was calculated based on Sentinel-2 datasets, which were acquired in the year 2019. The index was used for monitoring the surface condition of the source necessary for simulating Pb dispersion, because the higher surface water content reduces the intensity of windborne source. The results showed that the wind speeds and directions had huge impacts on Pb dispersion when the MNDWI had negative values, and that the dispersion was inhibited when the MNDWI had positive values. These indicate that the water content of the surface is sensitive to dispersion, and that MNDWI is an effective parameter that expresses the source strength.
  • Marthias Silwamba, Mayumi Ito, Naoki Hiroyoshi, Carlito Baltazar Tabelin, Ryota Hashizume, Tomoki Fukushima, Ilhwan Park, Sanghee Jeon, Toshifumi Igarashi, Tsutomu Sato, Imasiku Nyambe, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    Minerals 12 4 2022年04月 [査読有り]
     
    Zinc plant leach residues (ZPLRs), particularly those produced using old technologies, have both economic importance as secondary raw materials and have environmental impacts because they contain hazardous heavy metals that pose risks to human health and the environment. Therefore, the extraction and recovery of these metals from ZPLRs has both economic and environmental benefits. In this study, we investigated the removal of lead (Pb) and zinc (Zn) from ZPLRs by alkaline (NaOH) leaching and the concurrent cementation of dissolved Pb and Zn using aluminum (Al) metal powder. The effects of the leaching time, NaOH concentration, solid-to-liquid ratio (S/L), and dosage of Al metal powder on the extraction of Pb and Zn were investigated. Pb and Zn removal efficiencies increased with increasing NaOH concentrations and decreasing S/Ls. The Pb and Zn removal efficiencies were 62.2% and 27.1%, respectively, when 2.5 g/50 mL (S/L) of ZPLRs were leached in a 3 M NaOH solution for 30 min. The extraction of Pb and Zn could be attributed to the partitioning of these metals in relatively more mobile phases—water-soluble, exchangeable, and carbonate phases— in ZPLRs. Around 100% of dissolved Pb and less than 2% of dissolved Zn were cemented in leaching pulp when Al metal powder was added. Minerals in the solid residues, particularly iron oxides minerals, were found to suppress the cementation of extracted Zn in leaching pulp, and when they were removed by filtration, Zn was recovered by Al metal powder via cementation.
  • 奈良禎太, 加藤昌治, 佐藤 努, 河野勝宣, 佐藤稔紀
    Journal of MMIJ 138 4 44 - 50 2022年04月 [査読有り]
  • Sereyroith Tum, Kanako Toda, Tatsuya Matsui, Ryosuke Kikuchi, Sitha Kong, Panha Meas, Unsovath Ear, Yoko Ohtomo, Tsubasa Otake, Tsutomu Sato
    Science of The Total Environment 806 150398 - 150398 2022年02月 [査読有り]
  • Ayaka Murofushi, Tsubasa Otake, Kenzo Sanematsu, Kyaw Zay Ya, Akane Ito, Ryosuke Kikuchi, Tsutomu Sato
    Mineralium Deposita 2022年01月12日 [査読有り]
  • Walubita Mufalo, Pawit Tangviroon, Toshifumi Igarashi, Mayumi Ito, Tsutomu Sato, Meki Chirwa, Imasiku Nyambe, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    Toxics 9 10 2021年10月04日 [査読有り]
     
    Zambia's Kabwe mine wastes (KMWs) are responsible for contaminating the surrounding soil and dust in the Kabwe district. Unfortunately, these wastes arise from the historical mining activities of lead (Pb) and Zinc (Zn), which lacked adequate waste management strategies. As a result, potentially toxic elements (PTEs) (Pb and Zn) spread across the Kabwe district. To assess the soil pollution derived from previous mining activities, we studied topsoil samples (n = 8) from the school playground soils (SPs). In this study, the degree of contamination, geochemical partitioning, and leachability, coupled with the release and retention of Pb and Zn, were studied. The SPs were classified as extremely enriched (EF > 40) and contaminated with Pb (Igeo > 5). On average, Pb (up to 89%) and Zn (up to 69%) were bound with exchangeable, weak acid-soluble, reducible and oxidizable phases, which are considered as 'geochemically mobile' phases in the environment. The leachates from the soils (n = 5) exceeded the Zambian standard (ZS: 190:2010) for Pb in potable drinking water (Pb < 0.01 mg/L). Furthermore, the spatial distribution of Pb and Zn showed a significant reduction in contents of Pb and Zn with the distance from the mine area.
  • Shinsaku Nakamura, Toshifumi Igarashi, Yoshitaka Uchida, Mayumi Ito, Kazuyo Hirose, Tsutomu Sato, Walubita Mufalo, Meki Chirwa, Imasiku Nyambe, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    Minerals 11 8 2021年08月 
    Dispersion of lead (Pb) in mine wastes was simulated for reproducing Pb contamination of soil in Kabwe District, Zambia. Local weather data of year 2019 were monitored in situ and used for the simulations. The plume model, weak puff model, and no puff model were adopted for calculation of Pb dispersion under different wind conditions. The results showed that Pb dispersion from the Kabwe mine was directly affected by wind directions and speeds in the dry season, although it was not appreciably affected in the rainy season. This may be because the source strength is lower in the rainy season due to higher water content of the surface. This indicates that Pb dispersion patterns depend on the season. In addition, the distribution of the amount of deposited Pb-bearing soils around the mine corresponded to the distribution of Pb contents in soils. These results suggest that Pb contamination in soils primarily results from dispersion of fine mine wastes.
  • Akane Ito, Tsubasa Otake, Adi Maulana, Kenzo Sanematsu, Sufriadin, Tsutomu Sato
    Resource Geology 71 3 255 - 282 2021年07月 [査読有り]
  • Frances Chikanda, Tsubasa Otake, Aoi Koide, Akane Ito, Tsutomu Sato
    Science of The Total Environment 774 145183 - 145183 2021年06月 [査読有り]
  • Tsubasa Otake, Ryoichi Yamada, Ryohei Suzuki, Shunsuke Nakamura, Akane Ito, Ki-Cheol Shin, Tsutomu Sato
    Geochimica et Cosmochimica Acta 295 49 - 64 2021年02月 [査読有り]
  • M. Kato, Y. Nara, D. Fukuda, M. Kohno, Toshinori Sato, Tsutomu Sato, M. Takahashi
    Journal of the Society of Materials Science, Japan 70 4 300 - 306 2021年 [査読有り][通常論文]
     
    Because rock masses serve as natural barriers for geological disposal of radioactive waste, information about rock permeability is essential. An understanding of the influence of the surrounding environment temperature on the results is necessary for highly accurate permeability measurements. Herein we describe how to perform precise permeability measurements. Then, to investigate the influence of the surrounding environment temperature, we show the results of permeability measurements under conditions with dramatic changes using the transient pulse method and a Toki granite sample obtained from Gifu Prefecture in central Japan. The measured permeability without a temperature change is used as a reference. A change in the surrounding environment temperature remarkably affects the pressure in the upstream and downstream reservoirs, their pressure difference, and the confining pressure. An increase in the experimental system temperature increases the pressure. This difference is directly related to the estimated permeability. To accurately measure the rock permeability, it is essential to minimize changes in the surrounding environment temperature because they significantly affect the pressure difference.
  • Cryton Phiri, Daiki Shimazui, Tsubasa Otake, Ryosuke Kikuchi, Isaac Chintu, Meki Chirwa, Lawrence Kalaba, Imasiku Nyambe, Tsutomu Sato
    Science of The Total Environment 769 144342 - 144342 2020年12月 [査読有り]
  • Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki, Allison Arabelo, Kawawa Banda, Imasiku Nyambe, Meki Chirwa, Mayumi Ito, Tsutomu Sato, Toshifumi Igarashi, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    Scientific Reports 10 1 2020年12月 [査読有り]
     
    AbstractThe present study investigated biosorption of Pb (II) and Zn (II) using a heavy metal tolerant bacterium Oceanobacillus profundus KBZ 3-2 isolated from a contaminated site. The effects of process parameters such as effect on bacterial growth, pH and initial lead ion concentration were studied. The results showed that the maximum removal percentage for Pb (II) was 97% at an initial concentration of 50 mg/L whereas maximum removal percentage for Zn (II) was at 54% at an initial concentration of 2 mg/L obtained at pH 6 and 30 °C. The isolated bacteria were found to sequester both Pb (II) and Zn (II) in the extracellular polymeric substance (EPS). The EPS facilitates ion exchange and metal chelation-complexation by virtue of the existence of ionizable functional groups such as carboxyl, sulfate, and phosphate present in the protein and polysaccharides. Therefore, the use of indigenous bacteria in the remediation of contaminated water is an eco-friendly way of solving anthropogenic contamination.
  • Kanako Toda, Ryosuke Kikuchi, Tsubasa Otake, Satoshi Nishimura, Yuzoh Akashi, Michihiro Aimoto, Takeshi Kokado, Tsutomu Sato
    Materials 13 23 5450 - 5450 2020年11月30日 [査読有り]
     
    Dredged soils have been used as construction materials by alkaline activation with steel slag (steel slag-dredged soil mixtures) at harbors. Such mixtures develop strength chiefly by calcium silicate hydrate (C-S-H) formation by the pozzolanic reaction. However, the strength of such mixtures is unpredictable, and in some cases, mixtures have been too soft for the intended engineering application. An identification of strength development indicators would accelerate evaluation processes for strength development to facilitate and promote the utilization of such materials. This paper focuses on the relationship between the characteristics of soil organic matters in dredged soils and the strength development of the mixtures by a comparison of eight dredged soils collected from eight different Japanese harbors. The characteristics of the soil organic matters were identified to determine as indicators of mixtures with weak strength development, i.e., enriched sulfur content in extracted soil organic matter (humic acid) fraction, and the N/C ratio of humic acid similar to land humic acid standards. Increases in the validated fraction of dredged soils and steel slag by replacing fractions disadvantageous to construction resources would contribute to reduce waste production, which would lower the environmental impact of the use, aiming to achieve sustainable utilization of such materials.
  • Natatsawas Soonthornwiphat, Yutaro Kobayashi, Kanako Toda, Kazuma Kuroda, Chaerun Raudhatul Islam, Tsubasa Otake, Yogarajah Elakneswaran, John L. Provis, Tsutomu Sato
    Journal of Nuclear Science and Technology 57 10 1181 - 1188 2020年10月02日 [査読有り]
  • Pawit Tangviroon, Kenta Noto, Toshifumi Igarashi, Takeshi Kawashima, Mayumi Ito, Tsutomu Sato, Walubita Mufalo, Meki Chirwa, Imasiku Nyambe, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    MINERALS 10 9 2020年09月 [査読有り]
     
    Massive amount of highly contaminated mining residual materials (MRM) has been left unattended and has leached heavy metals, particularly lead (Pb) and zinc (Zn) to the surrounding environments. Thus, the performance of three immobilizers, raw dolomite (RD), calcined dolomite (CD), and magnesium oxide (MO), was evaluated using batch experiments to determine their ability to immobilize Pb and Zn, leached from MRM. The addition of immobilizers increased the leachate pH and decreased the amounts of dissolved Pb and Zn to different extents. The performance of immobilizers to immobilize Pb and Zn followed the following trend: MO > CD > RD. pH played an important role in immobilizing Pb and Zn. Dolomite in RD could slightly raise the pH of the MRM leachate. Therefore, the addition of RD immobilized Pb and Zn via adsorption and co-precipitation, and up to 10% of RD addition did not reduce the concentrations of Pb and Zn to be lower than the effluent standards in Zambia. In contrast, the presence of magnesia in CD and MO significantly contributed to the rise of leachate pH to the value where it was sufficient to precipitate hydroxides of Pb and Zn and decrease their leaching concentrations below the regulated values. Even though MO outperformed CD, by considering the local availability of RD to produce CD, CD could be a potential immobilizer to be implemented in Zambia.
  • Misato Shimbashi, Shingo Yokoyama, Yasutaka Watanabe, Tsutomu Sato, Tsubasa Otake, Ryosuke Kikuchi, Minoru Yamakawa, Naoki Fujii
    Minerals 10 8 719 - 719 2020年08月17日 [査読有り][通常論文]
     
    In radioactive waste disposal facilities, low-permeability engineered barrier materials are important for inhibiting radionuclide migration. However, dissolution–precipitation reactions under alkaline conditions change the permeability of engineered barriers. To understand long-term dissolution–precipitation reactions under alkaline conditions in chemically complex systems, trenches and drill holes were excavated at Narra in Palawan, where alkaline fluids (pH > 11) have been naturally produced, seeping into clastic sediments derived from serpentinized ultramafic rocks and gabbro of Palawan ophiolite. Interaction between the alkaline seepage and clastic sediments, which have been deposited since 15,000 radiocarbon years before present (14C yr BP), led to dissolution of minerals and the precipitation of Si-bearing phases which were divided into two main categories: Fe-Mg-Si infillings and Ca-Si infillings. The former category was composed of iron-magnesium-silicate-hydrate (F-M-S-H) and a nontronite-like mineral and was widely recognized in the clastic sediments. The nontronite-like mineral likely formed by interaction between silicates and alkaline seepage mixed with infiltrated seawater, whereas F-M-S-H formed by the reaction of silicates with alkaline seepage in the absence of seawater infiltration. Ca-Si infillings included 14 Å tobermorite and were precipitated from alkaline seepage combined with the Ca and Si supplied by the dissolution of calcite and silicates in the clastic sediments.
  • Marthias Silwamba, Mayumi Ito, Naoki Hiroyoshi, Carlito Baltazar Tabelin, Tomoki Fukushima, Ilhwan Park, Sanghee Jeon, Toshifumi Igarashi, Tsutomu Sato, Imasiku Nyambe, Meki Chirwa, Kawawa Banda, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING 8 4 2020年08月 [査読有り]
     
    Zinc plant leach residues (ZPLRs) are hazardous solid wastes generated from zinc metal production owing to their substantial contents of lead (Pb), a toxic heavy metal. This study investigated the detoxification of historic ZPLRs from Kabwe, Zambia by removing Pb using a coupled extraction-cementation method in chloride media. For the coupled extraction-cementation method, micro-scale zero-valent iron (mZVI) was added during ZPLRs leaching in acidified chloride solution. Cemented Pb on the surface of mZVI was recovered easily from the leaching pulp by magnetic separation. Pb removal was evaluated in different solution compositions (NaCl:1-5.13 M, HCl: 0-0.1 M) with and without the addition of mZVI. The addition of mZVI during ZPLRs leaching (i.e., coupled extraction-cementation) increased Pb removal from 3% to 24%, 1.3% to 27.5%, 5.2% to 34.9%, and 6.5% to 55.8% when NaCl concentration was fixed at 0.86 M and HCl concentrations were 0 M, 0.01 M, 0.05 M and 0.1 M, respectively. When NaCl concentration was increased above 3.42 M and HCl maintained at 0.1 M HCl, Pb removal increased to 80%. Analysis of the Pb-loaded mZVI (magnetic fraction) by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and X-ray photoelectron spectroscopy (XPS) revealed that Pb was recovered during leaching via cementation as Pb degrees. The toxicity characteristic leaching procedure (TCLP) and in vitro solubility and bioavailability research consortium gastric phase (SBRC-G) tests for Pb of ZPLRs before and after treatment decreased drastically from 11.3 to 3.5 mg/L (below 5 mg/L threshold) and 12 300 to 2 840 mg/Kg, respectively.
  • Wilson Mwandira, Kazunori Nakashima, Yuki Togo, Tsutomu Sato, Satoru Kawasaki
    Chemosphere 246 2020年05月01日 
    Intake of toxic trace elements in drinking water can lead to adverse health effects. To remove toxic trace elements from water, we developed a novel biosorbent composed of cellulose and a fusion protein. The fusion protein was constructed from metallothionein (MT) and a carbohydrate-binding module (CBM), where CBM can bind to cellulose while MT can capture heavy metal ions in solution. In a batch experiment, the biosorbent had maximum biosorption capacities for Pb(II) and Zn(II) ions of 39.02 mg/g and 29.28 mg/g, respectively. Furthermore, the biosorbent could be used in a semi-continuous system and showed good regeneration and recyclability. Both cellulose and the MT-CBM are environmentally friendly and renewable materials, and this biosorbent has great potential for efficient removal of toxic trace elements from polluted water.
  • Marthias Silwamba, Mayumi Ito, Naoki Hiroyoshi, Carlito Baltazar Tabelin, Ryota Hashizume, Tomoki Fukushima, Ilhwan Park, Sanghee Jeon, Toshifumi Igarashi, Tsutomu Sato, Meki Chirwa, Kawawa Banda, Imasiku Nyambe, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    Metals 10 4 531 - 531 2020年04月20日 [査読有り][通常論文]
     
    Zinc plant leach residues (ZPLRs) contain significant amounts of metal compounds of lead (Pb), zinc (Zn), iron (Fe), etc., hence, they are considered as a secondary source of metals. On the other hand, ZPLRs are regarded as hazardous materials because they contain heavy metals that pollute the environment. Resources and environmental concerns of ZPLRs were addressed in this study by removing/recovering Pb and Zn using a concurrent dissolution and cementation technique. To cement the dissolved Pb and Zn in leaching pulp, zero-valent aluminum (ZVAl) was added during ZPLRs leaching in the hydrochloric (HCl)–sodium chloride (NaCl) solution. The resulting cemented metals were agglomerated and separated by sieving. Lead removal increased with increasing both NaCl and HCl concentrations. However, when ZVAl was added, significant Pb removal was achieved at a low concentration. Zinc was not cemented out of the pulp using ZVAl and its recovery from ZPLRs was dependent on the HCl concentration only. By applying a concurrent dissolution and cementation technique, both Pb and Zn were removed using a low concentration of NaCl, and most importantly Pb—the most toxic metal in ZPLRs—was captured and separated before the solid-liquid separation, hence, eliminating the need for extensive washing of the generated residues to remove the inherent residual solution.
  • Geochemical characteristics of ores and surface waters for environmental risk assessment in the Pinpet iron deposit, southern Shan State, Myanmar
    K. Zay Ya, T. Otake, A. Koide, K. Sanematsu, T. Sato
    Resource Geology 70 2020年02月 [査読有り][通常論文]
  • Mwandira W, Nakashima K, Kawasaki S, Ito M, Sato T, Igarashi T, Chirwa M, Banda K, Nyambe I, Nakayama S, Nakata H, Ishizuka M
    Chemosphere 228 17 - 25 2019年08月 [査読有り][通常論文]
     
    Environmental impacts resulting from historic lead and zinc mining in Kabwe, Zambia affect human health due to the dust generated from the mine waste that contains lead, a known hazardous pollutant. We employed microbially induced calcium carbonate precipitation (MICP), an alternative capping method, to prevent dust generation and reduce the mobility of contaminants. Pb-resistant Oceanobacillus profundus KBZ 1–3 and O. profundus KBZ 2–5 isolated from Kabwe were used to biocement the sand that would act as a cover to prevent dust and water infiltration. Sand biocemented by KBZ 1–3 and KBZ 2–5 had maximum unconfined compressive strength values of 3.2 MPa and 5.5 MPa, respectively. Additionally, biocemented sand exhibited reduced water permeability values of 9.6 × 10−8 m/s and 8.9 × 10−8 m/s for O. profundus KBZ 1–3 and KBZ 2–5, respectively, which could potentially limit the entrance of water and oxygen into the dump, hence reducing the leaching of heavy metals. We propose that these isolates represent an option for bioremediating contaminated waste by preventing both metallic dust from becoming airborne and rainwater from infiltrating into the waste. O. profundus KBZ 1–3 and O. profundus KBZ 2–5 isolated form Kabwe represent a novel species that has, for the first time, been applied in a bioremediation study.
  • F. Chikanda, T. Otake, Y. Ohtomo, A. Ito, T. D. Yokoyama, T. Sato
    Minerals 9 7 442  2019年07月 [査読有り][通常論文]
     
    Carbonatites undergo various magmatic-hydrothermal processes during their evolution that are important for the enrichment of rare earth elements (REE). This geochemical, petrographic, and multi-isotope study on the Kangankunde carbonatite, the largest light REE resource in the Chilwa Alkaline Province in Malawi, clarifies the critical stages of REE mineralization in this deposit. The delta Fe-56 values of most of the carbonatite lies within the magmatic field despite variations in the proportions of monazite, ankerite, and ferroan dolomite. Exsolution of a hydrothermal fluid from the carbonatite melts is evident based on the higher delta Fe-56 of the fenites, as well as the textural and compositional zoning in monazite. Field and petrographic observations, combined with geochemical data (REE patterns, and Fe, C, and O isotopes), suggest that the key stage of REE mineralization in the Kangankunde carbonatite was the late magmatic stage with an influence of carbothermal fluids i.e. magmatic-hydrothermal stage, when large (similar to 200 mu m), well-developed monazite crystals grew. The C and O isotope compositions of the carbonatite suggest a post-magmatic alteration by hydrothermal fluids, probably after the main REE mineralization stage, as the alteration occurs throughout the carbonatite but particularly in the dark carbonatites.
  • Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki, Mayumi Ito, Tsutomu Sato, Toshifumi Igarashi, Kawawa Banda, Meki Chirwa, Imasiku Nyambe, Shouta Nakayama, Mayumi Ishizuka
    Environmental science and pollution research international 26 15 15653 - 15664 2019年05月 [査読有り][通常論文]
     
    Biocementation of hazardous waste is used in reducing the mobility of contaminants, but studies on evaluating its efficacy have not been well documented. Therefore, to evaluate the efficacy of this method, physicochemical factors affecting stabilized hazardous products of in situ microbially induced calcium carbonate precipitation (MICP) were determined. The strength and leach resistance were investigated using the bacterium Pararhodobacter sp. Pb-contaminated kiln slag (KS) and leach plant residue (LPR) collected from Kabwe, Zambia, were investigated. Biocemented KS and KS/LPR had leachate Pb concentrations below the detection limit of < 0.001 mg/L, resisted slaking, and had maximum unconfined compressive strengths of 8 MPa for KS and 4 MPa for KS/LPR. Furthermore, biocemented KS and KS/LPR exhibited lower water absorption coefficient values, which could potentially reduce the water transportation of Pb2+. The results of this study show that MICP can reduce Pb2+ mobility in mine wastes. The improved physicochemical properties of the biocemented materials, therefore, indicates that this technique is an effective tool in stabilizing hazardous mine wastes and, consequently, preventing water and soil contamination.
  • Kanako Toda, Haruna Sato, Nilan Weerakoon, Tsubasa Otake, Satoshi Nishimura, Tsutomu Sato
    Minerals 8 10 2018年10月22日 
    The authors wish to make the following corrections to this paper [1]: Toda, K. Sato, H. Weerakoon, N. Otake, T. Nishimura, S. Sato, T. Key Factors Affecting Strength Development of Steel Slag-Dredged Soil Mixtures. Minerals 2018, 8, 174. 1. Change in Main Body Paragraphs On page 2 of 16, lines 90–91, the sentence “Purified humic acid content was highest in soil D (2.04%) followed by C (1.23%), A (1.02%) and B (0.74%)” should be “Purified humic acid content was highest in soil D (0.30%) followed by B (0.20%), C (0.14%) and A (0.09%)”. Consequently, on page 11 of 16, lines 320–322, the sentence “This suggests that the content of humic acids in soils A, B, C and D (0.74–2.04%) is not sufficient to act as a pH buffer” should be “This suggests that the content of humic acids in soils A, B, C and D (0.09–0.30%) is not sufficient to act as a pH buffer”. These changes have no material impact on the conclusions of our paper. We apologize to our readers. 2. Change in Table Due to mislabeling, replace Table 2: Table 2. Mineral dissolution rates and surface areas of silica-bearing phases loaded in the geochemical modeling as reactants. (Table presented). Table 2. Mineral dissolution rates and surface areas of silica-bearing phases loaded in the geochemical modeling as reactants. (Table presented).
  • Jun Koarashi, Syusaku Nishimura, Mariko Atarashi-Andoh, Takeshi Matsunaga, Tsutomu Sato, Seiya Nagao
    Chemosphere 205 147 - 155 2018年08月01日 [査読有り][通常論文]
     
    The Fukushima Daiichi nuclear power plant accident caused serious radiocesium (137Cs) contamination in soils in a range of terrestrial ecosystems. It is well documented that the interaction of 137Cs with soil constituents, particularly clay minerals, in surface soil layers exerts strong control on the behavior of this radionuclide in the environment however, there is little understanding of how soil aggregation—the binding of soil particles together into aggregates—can affect the mobility and bioavailability of 137Cs in soils. To explore this, soil samples were collected at seven sites under different land-use conditions in Fukushima and were separated into four aggregate-size fractions: clay-sized (< 2 μm) silt-sized (2–20 μm) sand-sized (20–212 μm) and macroaggregates (212–2000 μm). The fractions were then analyzed for 137Cs content and extractability and mineral composition. In forest soils, aggregate formation was significant, and 69%–83% of 137Cs was associated with macroaggregates and sand-sized aggregates. In contrast, there was less aggregation in agricultural field soils, and approximately 80% of 137Cs was in the clay- and silt-sized fractions. Across all sites, the 137Cs extractability was higher in the sand-sized aggregate fractions than in the clay-sized fractions. Mineralogical analysis showed that, in most soils, clay minerals (vermiculite and kaolinite) were present even in the larger-sized aggregate fractions. These results demonstrate that larger-sized aggregates are a significant reservoir of potentially mobile and bioavailable 137Cs in organic-rich (forest and orchard) soils. Our study suggests that soil aggregation reduces the mobility of particle-associated 137Cs through erosion and resuspension and also enhances the bioavailability of 137Cs in soils.
  • Paul Clarence M. Francisco, Tsutomu Sato, Tsubasa Otake, Takeshi Kasama, Shinichi Suzuki, Hideaki Shiwaku, Tsuyoshi Yaita
    Environmental Science and Technology 52 8 4817 - 4826 2018年04月17日 [査読有り][通常論文]
     
    Understanding the form of Se(IV) co-precipitated with ferrihydrite and its subsequent behavior during phase transformation is critical to predicting its long-term fate in a range of natural and engineered settings. In this work, Se(IV)-ferrihydrite co-precipitates formed at different pH were characterized with chemical extraction, transmission electron microscopy (TEM), and X-ray absorption spectroscopy (XAS) to determine how Se(IV) is associated with ferrihydrite. Results show that despite efficient removal, the mode and stability of Se(IV) retention in the co-precipitates varied with pH. At pH 5, Se(IV) was removed dominantly as a ferric selenite-like phase intimately associated with ferrihydrite, while at pH 10, it was mostly present as a surface species on ferrihydrite. Similarly, the behavior of Se(IV) and the extent of its retention during phase transformation varied with pH. At pH 5, Se(IV) remained completely associated with the solid phase despite the phase change, whereas it was partially released back into solution at pH 10. Regardless of this difference in behavior, TEM and XAS results show that Se(IV) was retained within the crystalline post-aging products and possibly occluded in nanopore and defect structures. These results demonstrate a potential long-term immobilization pathway for Se(IV) even after phase transformation. This work presents one of the first direct insights on Se(IV) co-precipitation and its behavior in response to iron phase transformations.
  • Shuang Zhou, Tsutomu Sato, Tsubasa Otake
    Minerals 8 3 101  2018年03月05日 [査読有り][通常論文]
     
    Elevated antimony concentrations in aqueous environments from anthropogenic sources are becoming of global concern. In this respect iron oxides are known to strongly adsorb aqueous antimony species with different oxidation states, but the effect of silica on the removal characteristics is not well understood despite being a common component in the environment. In this study, ferrihydrite was synthesized at various Si/Fe molar ratios to investigate its adsorption and co-precipitation behaviors with aqueous antimony anionic species, Sb(III) and Sb(V). The X-ray diffraction analyses of the precipitates showed two broad diffraction features at approximately 35° and 62° 2θ, which are characteristics of 2-line ferrihydrite, but no significant shifts in peak positions in the ferrihydrite regardless of the Si/Fe ratios. The infrared spectra showed a sharp band at ~930 cm−1, corresponding to asymmetric stretching vibrations of Si–O–Fe bonds which increased in intensity with increasing Si/Fe molar ratios. Further, the surface charge on the precipitates became more negative with increasing Si/Fe molar ratios. The adsorption experiments indicated that Sb(V) was preferentially adsorbed under acidic conditions which decreased dramatically with increasing pH while the adsorption rate of Sb(III) ions was independent of pH. However, the presence of silica suppressed the adsorption of both Sb(III) and Sb(V) ions. The results showed that Sb(III) and Sb(V) ions were significantly inhibited by co-precipitation with ferrihydrite even in the presence of silica by isomorphous substitution in the ferrihydrite crystal structure.
  • 加藤昌治, 奈良禎太, 岡崎勇樹, 河野勝宣, 佐藤稔紀, 佐藤努, 高橋学
    材料 67 3 318 - 323 2018年03月01日 [査読有り][通常論文]
     
    To ensure the safe geological disposal of radioactive wastes, it is important to determine the permeability of clays. The transient pulse test is suitable to apply to the low permeability materials, because it takes relatively short term to determine the permeability. Usually we increase the upstream pore pressure in the measurement with the transient pulse test. However, it is impossible to determine the permeability of clay in this procedure because of the increase of pore pressure. Therefore, the transient pulse test has never been applied to the determination of permeability of clays. In this study, we tried to apply the transient pulse test to a clay obtained in Mizunami Underground Research Laboratory to determine the permeability with decreasing the downstream pore pressure. It was clarified that the transient pulse test with decreasing downstream pore pressure is appropriate from the measurement of granite. It was shown that the permeability of a clay was determined by the transient pulse test with decreasing the downstream pore pressure, which agreed with the permeability determined from the falling head test. The measurement time of the transient pulse test is much shorter than that of the falling head test. It is concluded that the transient pulse test is appropriate for the determination of the permeability of clays.
  • Shoko Nozawa, Tsutomu Sato, Tsubasa Otake
    Minerals 8 2 76  2018年02月24日 [査読有り][通常論文]
     
    The effect of silica on the immobilization reaction of boron by magnesium oxide was investigated by laboratory experiments. In the absence of silica, due to dissolution of the magnesium oxide, boron was removed from solutions by the precipitation of multiple magnesium borates. In the presence of silica, magnesium silica hydrate (M-S-H) was formed as a secondary mineral, which takes up boron. Here11 B magic-angle spinning nuclear magnetic resonance (MAS-NMR) and Fourier transform infrared spectrometer (FT-IR) data show that a part of the boron would be incorporated into M-S-H structures by isomorphic substitution of silicon. Another experiment where magnesium oxide and amorphous silica were reacted beforehand and boron was added later showed that the shorter the reaction time of the preceding reaction, the higher the sorption ratio of boron. That is, boron was incorporated into the M-S-H mainly by coprecipitation. The experiments in the study here show that the sorption of boron in the presence of silica is mainly due to the incorporation of boron during the formation of the M-S-H structure, which suggests that boron would not readily leach out, and that stable immobilization of boron can be expected.
  • Lei Li, Guangxia Qi, Bangda Wang, Dongbei Yue, Yi Wang, Tsutomu Sato
    JOURNAL OF HAZARDOUS MATERIALS 343 19 - 28 2018年02月 [査読有り][通常論文]
     
    A novel multifunctional composite adsorbent which possesses the ability for anion exchange and toxic metal complexation has been synthesized by the hybridization of layered double hydroxides (LDH) and fulvic acid (FA) in this study. The results show that FA with lots of functional groups can be effectively and stably anchored on the surface of LDH through coagulation process without occupying the interlayer of LDH. Therefore, the anion exchange ability remains and the adsorption capacity of Orange II can reach 1.9 mmol/g, which is almost as much as stoichiometric anion exchange capacity of pure LDH. Moreover, the composite adsorbent's adsorption capacity of Cu2+, Pb2+, Ni2+ and Cd2+ can also get to 2.25 mmol/g, 0.98 mmol/g, 0.99 mmol/g and 0.16 mmol/g respectively with an adsorption preference order of Cu2+ > Pb2+ > Ni2+ > Cd2+. In addition, Orange II and toxic metals are able to be simultaneously removed by this composite adsorbent, and the adsorption of toxic metals can be enhanced by the synergetic adsorption of Orange II. Anion exchange with Cl- in LDH matrix accounts for the adsorption of Orange II, while the adsorption of toxic metal is mainly attributed to the complexation of carboxyl functional group derived from FA. (C) 2017 Elsevier B.V. All rights reserved.
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  • Zigong Ning, Munehide Ishiguro, Luuk K. Koopal, Tsutomu Sato, Jun’ichi Kashiwagi
    J. Radioanalytical and Nuclear Chemistry 317 409 - 419 2018年 [査読有り][通常論文]
  • Weerakoon, N, Nishimura, S, Sato, H, Toda, K, Sato, T, Arai, Y
    Ground Improvement AoP 2018年 [査読有り][通常論文]
  • ナチュラルアナログ研究のすゝめ
    佐藤 努
    原子力バックエンド研究 25 2 113 - 118 2018年 [査読有り][通常論文]
  • Nara, Y, Kato, M, Niri, R, Kohno, M, Sato, T, Fukuda, D, Sato, T, Takahashi, M
    Pure and Applied Geophysics. 175 3 917 - 927 2018年 [査読有り][通常論文]
     
    Information on the permeability of rock is essential for various geoengineering projects, such as geological disposal of radioactive wastes, hydrocarbon extraction, and natural hazard risk mitigation. It is especially important to investigate how fractures and pores influence the physical and transport properties of rock. Infiltration of groundwater through the damage zone fills fractures in granite with fine-grained minerals. However, the permeability of rock possessing a fracture naturally filled with fine-grained mineral grains has yet to be investigated. In this study, the permeabilities of granite samples, including a macro-fracture filled with clay and a mineral vein, are investigated. The permeability of granite with a fine-grained mineral vein agrees well with that of the intact sample, whereas the permeability of granite possessing a macro-fracture filled with clay is lower than that of the macro-fractured sample. The decrease in the permeability is due to the filling of fine-grained minerals and clay in the macro-fracture. It is concluded that the permeability of granite increases due to the existence of the fractures, but decreases upon filling them with fine-grained minerals.
  • Atsushi Mukunoki, Takahiro Kikuchi, Tamotsu Chiba, Tomofumi Sakuragi, Toshihiro Kogure, Tsutomu Sato
    MRS Advances 3 21 1139 - 1145 2018年 [査読有り][通常論文]
     
    Development of an iodine immobilization technique that can fix radioactive iodine in waste form for a long period and constrain its leaching into pore water is necessary in order to secure the long-term safety of geological disposal of transuranic (TRU) waste. Lead borate glass vitrified at a low temperature is regarded as one of the promising immobilization materials of Iodine-129 which will be removed from spent AgI filters generated from reprocessing plants and may have a significant effect on long term safety of geological disposal. Leaching experiments in bentonite-equilibrium water have been conducted to understand the lead borate glass dissolution behaviors in possible geological disposal conditions. Boron dissolved with the highest rate in all types of the solutions and was regarded as an index element to represent the glass dissolution rate. On the other hand, lead dissolved with a far slower rate. The chemical species and possible precipitating minerals of lead were examined by a geochemical calculation code for typical underground water. Altered glass surfaces were investigated by SEM, TEM and XRD. XRD analysis showed that the main constituent phase of the altered layer was hydrocerussite, Pb3(CO3)2(OH)2, that was predicted by the geochemical simulation as well.
  • Toda, K, Sato, H, Weerakoon, N, Otake, T, Nishimura, S, Sato, T
    Minerals 8 5 174 - 174 2018年 [査読有り][通常論文]
  • Application of the transient pulse method to measure clay permeability
    Kato, M, Nara, Y, Okazaki, Y, Kohno, M, Sato, T, Sato, T, Takahashi, M
    Materials Transaction 59 9 1427 - 1432 2018年 [査読有り][通常論文]
  • Tsutomu Sato
    Highlights in Applied Mineralogy 153 - 169 2017年12月18日 [査読有り][通常論文]
  • Youko Takahatake, Atsuhiro Shibata, Kazunori Nomura, Tsutomu Sato
    MINERALS 7 12 247 - 261 2017年12月 [査読有り][通常論文]
     
    Radioactive contaminated water has been generated at the Fukushima Daiichi Nuclear Power station (F1NPS). Hydrous sodium titanate (SrTreat (R)) is able to remove radioactive Strontium (Sr) from this water. Knowing the amount of radioactive nuclides in the used as-received SrTreat (R) is important for effective disposal and deposition of the F1NPS waste. This study investigated changes in the ability of SrTreat (R) to sorb Sr, and to understand the causes of changes in the sorbing. An investigation of the Sr sorption ability of SrTreat (R) is important for calculating the initial radioactive inventory of used SrTreat (R). This study carries out Sr sorption studies with acid-base titrations and X-ray photoelectron spectroscopy (XPS) to characterize the properties. After exposure to simulated treated water for 99 h, the surface structure of the SrTreat (R) was changed, and the percentage of sorbed Sr and the buffer capacity for protons decreased. When the amount of radioactive nuclides contained in the used SrTreat (R) is calculated from the sorption data of the as-received SrTreat (R), the radioactive Sr content will be overestimated with a concomitant increase in the deposition and disposal costs of the used SrTreat (R).
  • Akane Ito, Tsubasa Otake, Ki-Cheol Shin, Kamar Shah Ariffin, Fei-Yee Yeoh, Tsutomu Sato
    APPLIED GEOCHEMISTRY 82 89 - 101 2017年07月 [査読有り][通常論文]
     
    The environmental impacts of a heavy mineral processing involving rare earth elements (REEs) in the Kinta River and its tributaries near Ipoh city in Malaysia is investigated using geochemical and isotopic signatures and geochemical modeling. Analysis of water, sediment, suspended particulate matter, and rock samples reveals that stream waters close to the heavy mineral processing plant site are anthropogenically influenced, as indicated by slightly low pH (4.98-6.24) and elevated concentrations of Fe (up to 129 mg/L), Cl- (1540 mg/L), total REEs (1580 mu g/L), U (17.2 mu g/L), and Th (0.33 mu g/L). REE patterns and Pb isotope ratios of waters and sediments from a tributary are similar to those of tailings pond seepage and sediments, suggesting that not only these elements but also U and Th are derived from heavy mineral processing. The delta Fe-56 values of water in the tributary decrease downstream, accompanied by a decrease in Fe concentration, which is likely due to isotope fractionation via oxidative precipitation of Fe hydroxides. The concentrations of REEs, U, and Th decrease downstream, accompanied by an increase in pH, with different removal factors (Th > U > REEs). The influence of contamination is confined to within similar to 1.5 km downstream of the source. Tamm's acid oxalate extraction (to dissolve only low crystalline phases) showed that Th and Al concentrations were lower while U and Fe concentrations were higher in downstream suspended particulate samples, suggesting that Th and U may be removed by different mechanisms from stream water. The results of geochemical modeling suggest that Th precipitated as a solid phase, such as an intermediate between ThO2 and Th(OH)(4), with increasing stream water pH. In contrast, U may have been removed by adsorption onto Fe hydroxides, as supported by surface complexation modeling. The geochemical signatures and processes discussed in this study may be applicable for environmental assessment of REE processing. (C) 2017 Elsevier Ltd. All rights reserved.
  • Haruko Hase, Toru Nishiuchi, Tsutomu Sato, Tsubasa Otake, Tsuyoshi Yaita, Tohru Kobayashi, Tetsuro Yoneda
    JOURNAL OF HAZARDOUS MATERIALS 329 49 - 56 2017年05月 [査読有り][通常論文]
     
    Heavy metals contained in wastewater are generally removed by adding antalkaline to increase the pH, and Ni is commonly precipitated as Ni-hydroxides at pH 10. However, a more sustainable remediation method of treatment at neutral conditions would be attractive due to the high cost of chemical reagents and inefficient treatment at present. Based on natural attenuation, the method of adding Al ions has been used in wastewater treatment to precipitate layered double hydroxides (LDH). Here, we investigated the use of Al ion addition in the Ni containing wastewater treatment, experimentally and thermodynamically. By co-precipitation experiments adding Al ions to Ni-containing water, Ni was selectively incorporated into the structure of LDH, and the removal efficiency of Ni was close to 100% even in pH 7 and 8 samples (lower pH than conventional methods) with initial Ni concentrations of 200-10,000 mg/L. Geochemical modeling results replicate the experimental results well when the Al/Ni ratio of LDH is assumed to be 0.33. This model makes it possible to estimate the amount of Al ions and additive agents necessary for use in treatment of wastewater containing different Ni concentrations. (C) 2017 Elsevier B.V. All rights reserved.
  • 西方 美羽, 大友 陽子, 大竹 翼, 木村 勇気, 川本 大祐, 佐藤 努
    日本地球化学会年会要旨集 64 310 - 310 一般社団法人日本地球化学会 2017年 

    縞状鉄鉱層中のクロムのホスト鉱物はクロムスピネルであるがその起源は明らかになっていない。本研究では縞状鉄鉱層の初期沈殿物を模した鉄、クロム水酸化物を合成しフロースルー型実験装置を用いて二価鉄を含む150℃の熱水と1週間反応させた。生成物の固体分析の結果から主生成物がゲーサイトでありさらにスピネル鉱物が生成していることがわかった。さらにSEM分析ではスピネル様の結晶が観察でき、TEM分析からスピネル鉱物と同様の面間隔の値を持つクロムを含むスピネル様の粒子の凝集体が観察されたことからクロムスピネルが熱水実験により合成されたことが明らかになった。

  • 中島 亮, 大友 陽子, 大竹 翼, 掛川 武, 佐藤 努
    日本地球化学会年会要旨集 64 308 - 308 一般社団法人日本地球化学会 2017年 

    大酸化イベント以前の縞状鉄鉱層の形成プロセスについて、シアノバクテリアもしくは鉄酸化細菌が関与していたとする説が提案されている。本研究では約32億年前の南アフリカ・バーバトン緑色岩帯ムーディーズ層群の縞状鉄鉱層中有機物の各種分析から当時の生物活動に制約を与えることを目的とした。試料は磁鉄鉱に富むシルト質砂岩(MT)、炭酸塩に富み粒径の大きい石英を含む砂岩(SD)、粒径の小さい石英、緑泥石、黒雲母からなるシルト質砂岩(SS)に分類した。有機炭素含有量は鉄含有量の増加につれて減少する傾向がみられた一方、炭酸塩含有量と鉄含有量は正相関を示した。また有機物の形状は大部分が直径30 μm程度の円形ないし楕円形に近い鱗片状で、SD、SSにのみ長さ100μm以上のフィラメント状組織が見られた。以上の結果は、沿岸部の砂岩堆積場ではシアノバクテリアが、遠洋域のシルト質砂岩堆積場では鉄酸化細菌が生息していたことを示唆する。

  • Laboratory estimation of stiffness and strength mobilization in steel slag-mixed dredged clays with curing time
    Weerakoon, N, Nishimura, S, Sato, H, Toda, K, Sato, T, Arai, Y
    Proceedings of the 3rd International Conference on Ground Improvement and Ground Control, Hangzhou 2017年 [査読無し][通常論文]
  • Key Factors of Metastable Formation For Strength Development In Steel Slag-Dredged Soil Mixtures
    Toda, K, Otake, T, Sato, T, Weerakoon, N, Sato, H, Nishimura S
    International Symposium on Earth Resources Management & Environment, Colombo 2017年 [査読無し][通常論文]
  • Effect of silica-bearing phases in dredged soil on the strength development of steel slag-dredged soil mixtures
    Toda, K, Arai, Y, Otake, T, Sato, T, Weerakoon, N, Sato, H, Nishimura S
    16th International Clay Conference, Granada 2017年 [査読無し][通常論文]
  • 鈴木啓三, 佐藤努, 米田哲朗
    粘土科学 55 2 31 - 41 日本粘土学会 2017年 [査読有り][通常論文]
  • 安楽総太郎, 松原勇武, 森本和也, 佐藤努
    粘土科学 55 2 17 - 30 日本粘土学会 2017年 [査読有り][通常論文]
  • Zigong Ning, Munehide Ishiguro, Luuk K. Koopal, Tsutomu Sato, Jun'ichi Kashiwagi
    SOIL SCIENCE AND PLANT NUTRITION 63 1 14 - 17 2017年 [査読有り][通常論文]
     
    Behavior of radioactive strontium (Sr2+) in contaminated soils is an important issue in relation to nuclear power plant accidents. The Sr2+ adsorption on kaolinite and its migration in a kaolinite soil were investigated because toxic effects of radioactive Sr2+ have been found to be very severe for living organisms at low Sr2+ concentrations. Adsorption isotherms of Sr2+ on kaolinite at different salt (NaCl) concentration and pH were obtained by the batch method. The calculated distribution coefficients (K-D) ranged between 600 and 40,000 L kg(-1), which showed a strong preference for the adsorbed phase. The results were used to evaluate the ratio (r) of penetration length of Sr2+ relative to that of water in a model kaolinite soil. When the Sr2+ solution was percolated constantly into the kaolinite soil, the penetration of Sr2+ was delayed strongly at low Sr2+ concentration due to adsorption. The Sr2+ penetration length was only 0.001-0.056 of the water penetration length at pH 6.5 (0.1-10 mmol L-1 NaCl). At pH 4.1 (1 mmol L-1 NaCl) the effect was about 17 times less than at pH 6.5 (1 mmol L-1 NaCl). Under all conditions, the Sr2+ penetration increased when the Sr2+ concentration increased due to the KD decrease. The Sr2+ isotherms could be fitted well to the Langmuir adsorption equation, which indicates that only one site type is involved in the Sr2+ adsorption.
  • Microstructural properties of hardened cement paste blended with coal fly ash, sugar mill lime sludge and rice hull ash
    Opiso, E, Sato, Otake, T
    Advances in Concrete Construction, 5 3 289 - 301 2017年 [査読有り][通常論文]
  • Adsorption and post adsorption behavior of schwertmannite with various oxyanions
    Khamphila, K, Kodama, R, Sato, T, Otake, T
    J. Min. and Mat. Character. Eng. 5 90 - 106 2017年 [査読有り][通常論文]
  • 土壌のpH緩衝作用とそのモデリング
    佐藤努, 野澤笑子, 西田崇人
    土壌の物理性 135 41 - 46 2017年 [査読有り][招待有り]
  • 土壌の溶融生成物の鉱物学的および化学的特性
    万福 裕造, 八田 珠郎, 矢板 毅, 佐藤 努
    粘土科学 56 28 - 40 2017年 [査読有り][通常論文]
  • Takeshi Matsunaga, Takahiro Nakanishi, Mariko Atarashi-Andoh, Erina Takeuchi, Kotomi Muto, Katsunori Tsuduki, Syusaku Nishimura, Jun Koarashi, Shigeyoshi Otosaka, Tsutomu Sato, Yoshiki Miyata, Seiya Nagao
    JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY 310 2 679 - 693 2016年11月 [査読有り][通常論文]
     
    Particulate Cs-137 was collected from stream water for 2 years to assess the long-term trend of Cs-137 discharge from a forest after the Fukushima Nuclear Power Plant accident. A seasonal increase in the fluvial transport load of particulate Cs-137 in suspended solids (SS) was observed in July-October when rainfall was abundant. The Cs-137 load was controlled by the SS load. This control was attributed to cesium affinity for phyllosilicate clay minerals as verified by the low extractability of particulate Cs-137. These findings indicate the fluvial particulate Cs-137 load is significantly related to the climate and geomorphological features of Japan.
  • Paul Clarence M. Francisco, Tsutomu Sato, Tsubasa Otake, Takeshi Kasama
    AMERICAN MINERALOGIST 101 9-10 2057 - 2069 2016年09月 [査読有り][通常論文]
     
    Fe3+ minerals are ubiquitous in diverse near-surface environments, where they exert important controls on trace species transport. In alkaline environments such as the glass-steel interface in geological high-level radioactive waste disposal sites that use cement for plugging and grouting, Fe minerals are closely associated with Si that may affect their crystallization behavior as well as their capacities to regulate hazardous element cycling. While it is well known that Si retards Fe mineral crystallization, there is currently an overall lack of quantitative information on the rates of crystallization of stable Fe minerals in the presence of Si at alkaline conditions. Crystallization of Fe3+ minerals goethite and hematite from ferrihydrite co-precipitated with different amounts of Si was studied at pH 10 and at temperatures ranging from 50 to 80 degrees C using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). Mineral abundances evaluated from Rietveld refinement of XRD data show that the proportion of goethite in the final assemblage decreases relative to hematite with increasing Si. TEM observation of goethite and hematite crystals formed in the presence of Si show significant morphological differences compared to those formed in the absence of Si. Rate constants for crystallization derived from fitting of time-dependent changes in mineral abundances with the Avrami equation show a decreasing trend with increasing Si for both goethite and hematite. Apparent activation energies for crystallization for both minerals increase with increasing Si, with that of goethite increasing more drastically compared to hematite, indicating the inhibitive effect of Si on the crystallization of both minerals. The overall inhibition of crystallization may be explained in terms of the effects of Si on the surface properties of the ferrihydrite precursor. The rate constants and apparent activation energies reported in this study may be useful in estimating the crystallization behavior and timescales of Fe minerals in both natural and engineered environments. This information may eventually be helpful in predicting the fate of hazardous elements in such environments.
  • T. Yoneda, T. Watanabe, T. Sato
    CLAY MINERALS 51 4 653 - 674 2016年09月 [査読有り][通常論文]
     
    Chlorite (C)-corrensite (Co)-smectite (S) seriesminerals occur as vein constituents in the two epithermal ore veins, the Chuetsu and Shuetsu veins of the Todoroki Au-Ag deposit. The characteristics of the C-Co-S seriesminerals indicate that the clays may be products of direct precipitation from hydrothermal fluids and subsequent mineralogical transformations during and/or after vein formation. The minerals from the Chuetsu vein are characterized by 'monomineralic' corrensite showing an extensive distribution throughout the vein, and trioctahedral smectite occurring locally. The Shuetsu vein minerals are characterized by C-Co series minerals which can be divided into three different types: a I type including discrete chlorite with minor amounts of S layers, a II type comprising interstratified C/Co and discrete chlorite, and a III type characterized by segregation structures of C and Co layers. The C-Co series minerals show slightly different spatial distributions in the Shuetsu vein. Different epithermal environments during the vein formations and possible kinetic effects may have played a role in the formation and conversion of Co-C series at the Shuetsu vein and S-Co series at the Chuetsu vein.
  • Masaji Kato, Yoshitaka Nara, Daisuke Fukuda, Masanori Kohno, Toshinori Sato, Tsutomu Sato, Manabu Takahashi
    Zairyo/Journal of the Society of Materials Science, Japan 65 7 489 - 495 2016年07月01日 [査読有り][通常論文]
     
    Rock masses serve a vital function as natural barriers for geological disposal of radioactive waste therefore, information on rock permeability is essential. Highly accurate measurement of permeability requires understanding of how temperature changes in the surrounding environment influence measurement results. We performed permeability measurement under conditions with dramatic changes of temperature in the surrounding environment to investigate the influence of such changes on the experimental results. Measurement of permeability with no temperature change was also conducted as reference. All measurements were conducted using the transient pulse method, and the sample material used was Toki granite obtained from Gifu Prefecture in central Japan. We found that temperature changes in the surrounding environment remarkably affected the pressure in reservoirs upstream and downstream, the pressure difference between them, and the confining pressure all increased when temperature increased for our experimental system. Notably, pressure difference was affected immediately. This difference directly relates to estimation of permeability. As temperature changes significantly affect pressure difference, it is essential to minimize temperature changes in the surrounding environment so as to achieve accurate measurement of rock permeability.
  • Sylvain Grangeon, Francis Claret, Cedric Roosz, Tsutomu Sato, Stephane Gaboreau, Yannick Linard
    JOURNAL OF APPLIED CRYSTALLOGRAPHY 49 771 - 783 2016年06月 [査読有り][通常論文]
     
    The structure of nanocrystalline calcium silicate hydrates (C-S-H) having Ca/Si ratios ranging between 0.57 +/- 0.05 and 1.47 +/- 0.04 was studied using an electron probe micro-analyser, powder X-ray diffraction, 29 Si magic angle spinning NMR, and Fourier-transform infrared and synchrotron X-ray absorption spectroscopies. All samples can be described as nanocrystalline and defective tobermorite. At low Ca/Si ratio, the Si chains are defect free and the Si Q(3) and Q(2) environments account, respectively, for up to 40.2 +/- 1.5% and 55.6 +/- 3.0% of the total Si, with part of the Q(3) Si being attributable to remnants of the synthesis reactant. As the Ca/Si ratio increases up to 0.87 +/- 0.02, the Si Q(3) environment decreases down to 0 and is preferentially replaced by the Q(2) environment, which reaches 87.9 +/- 2.0%. At higher ratios, Q(2) decreases down to 32.0 +/- 7.6% for Ca/Si = 1.38 +/- 0.03 and is replaced by the Q(1) environment, which peaks at 68.1 +/- 3.8%. The combination of X-ray diffraction and NMR allowed capturing the depolymerization of Si chains as well as a two-step variation in the layer-to-layer distance. This latter first increases from similar to 11.3 angstrom (for samples having a Ca/Si ratio <similar to 0.6) up to 12.25 angstrom at Ca/Si = 0.87 +/- 0.02, probably as a result of a weaker layer-to-layer connectivity, and then decreases down to 11 angstrom when the Ca/Si ratio reaches 1.38 +/- 0.03. The decrease in layer-to-layer distance results from the incorporation of interlayer Ca that may form a Ca(OH)(2)-like structure, nanocrystalline and intermixed with C-S-H layers, at high Ca/Si ratios.
  • Einstine M. Opiso, Tsutomu Sato, Tetsuro Yoneda
    APPLIED CLAY SCIENCE 123 121 - 128 2016年04月 [査読有り][通常論文]
     
    This study examines the possible immobilization of Se(VI) by Mg-bearing hydrotalcite and serpentine-like minerals. Selenate immobilization was carried out via adsorption and coprecipitation reactions under alkaline conditions. The effects of Mg/Al ratios, temperature and initial Se concentration on the adsorption and/or coprecipitation of Se6+ onto these Mg-bearing minerals were examined. The sorption mechanism of Se(VI) was examined by XAFS analysis to give account of its local coordination environment. The results showed that Se(VI) sorption behavior by hydrotalcite and serpentine-like minerals was mainly influenced by their Mg/Al ratio. Higher removal efficiency of Se(VI) (> 60 and 90% at 100 and 10 ppm initial Se concentration) was observed during coprecipitation onto hydrotalcite and serpentine-like phases with Mg/Al ratios of 2 and 1.25, respectively. The formation of Mg-bearing minerals was enhanced at higher temperature (at 75 degrees C) but the effect of temperature in Se(VI) immobilization was very minimal. Selenate was mainly retained via outer-sphere complexation but an irreversible fraction of sorbed selenate (about 20%) was observed in these mineral phases. In overall, this study has several important implications in the possible application of hydrotalcite and aluminian serpentine in Se(VI) immobilization. (C) 2016 Elsevier B.V. All rights reserved.
  • Kazuya Morimoto, Kenji Tamura, Hirohisa Yamada, Tsutomu Sato, Masaya Suzuki
    APPLIED CLAY SCIENCE 121 71 - 76 2016年03月 [査読有り][通常論文]
     
    The syntheses of Mg-Fe(III) layered double hydroxides with different compositions at varied temperature through a co-precipitation method were attempted. The well -crystallized and white colored layered double hydroxides with chloride anions were obtained from the samples adjusted to the composition of Mg/Fe = 4 and aged at higher temperature. The Fe species in the white colored Mg-Fe layered double hydroxides were evaluated as all Fe(III) species by a Mossbauer measurement. The synthesized Mg-Fe(III) layered double hydroxide was treated with a sugar alcohol at temperature above its melting point in order to reduce Fe(III) incorporated into the hydroxide layers. The Mg -Fe layered double hydroxide resulting from a sugar alcohol treatment showed the reduction property in an aqueous solution. (C) 2015 Elsevier B.V. All rights reserved.
  • Einstine Opiso, Tsutomu Sato, Tetsuro Yoneda
    INTERNATIONAL JOURNAL OF OIL GAS AND COAL TECHNOLOGY 12 2 197 - 209 2016年 [査読有り][通常論文]
     
    Understanding the interaction of non-crystalline aluminosilicates with arsenate has environmental implications in controlling the mobility of dissolved anionic species in circum-neutral conditions during the utilisation and disposal of coal fly ash. This study focused on the determination of mineral phases in Si-Al system formed at circum-neutral pH condition and their interaction with arsenate in relation to the effect of temperature. The coprecipitation and surface adsorption behaviour of arsenate in the mineral phases formed was examined at 25, 50 and 75 degrees C. To determine arsenic association with the minerals, leaching test using phosphate bearing solution was also conducted. The results showed that allophane-like material was formed at relatively lower Si/Al ratio of 0.67 and amorphous aluminosilicates at higher Si/Al ratio of 1.5. Allophane showed higher arsenate removal efficiency of more than 90% during coprecipitation experiments compared to amorphous aluminosilicates. Moreover, allophane and amorphous aluminosilicates showed lower arsenate desorption efficiency of less than 20%. A significant irreversible fraction of sorbed arsenate was also observed which could be attributed to inner-sphere complex formation and the possible incorporation within the mineral structure. Hence, these non-crystalline minerals can act as chemical barrier for dissolved anionic species during the utilisation and disposal of coal fly ash.
  • Determination of Lead Contamination in Urban Soil, Yogyakarta City, Indonesia
    Aye, S.A.Z, Hendrayana, H, Putra, D.P.E, Sato, T
    Applied Mechanics and Materials 842 473 - 477 2016年 [査読有り][通常論文]
  • Morphology control of clay-mineral particles as supports for metallocene catalysts in propylene polymerization
    Tayano, T, Sagae, T, Atsumi, T, Uchino, H, Murata M, Sato, T
    Polyolefins Journal 3 79 - 92 2016年 [査読有り][通常論文]
  • 岩石の透水試験における環境温度の制御の重要性
    加藤昌治, 奈良禎太, 福田大祐, 河野勝宣, 佐藤稔紀, 佐藤努, 高橋学
    材料 65 282 - 287 2016年 [査読有り][通常論文]
  • Kazuya Morimoto, Kenji Tamura, Sohtaro Anraku, Tsutomu Sato, Masaya Suzuki, Hirohisa Yamada
    JOURNAL OF SOLID STATE CHEMISTRY 228 221 - 225 2015年08月 [査読有り][通常論文]
     
    The synthesis of Zn-Fe(III) layered double hydroxides was attempted, employing different pathways using either Fe(II) or Fe(III) species together with Zn as the initial reagents. The product derived from the synthesis employing Fe(II) was found to transition to a Zn-Fe(III) layered double hydroxides phase following oxidation process. In contrast, the product obtained with Fe(III) did not contain a layered double hydroxides phase, but rather consisted of simonkolleite and hydrous ferric oxide. It was determined that the valency of the Fe reagent used in the initial synthesis affected the generation of the layered double hydroxides phase. Fe(II) species have ionic radii and electronegativities similar to those of Zn, and therefore are more likely to form trioctahedral hydroxide layers with Zn species. (C) 2015 Elsevier Inc. All rights reserved.
  • Masako Yoshikawa, Marie Python, Akihiro Tamura, Shoji Arai, Eiichi Takazawa, Tomoyuki Shibata, Akira Ueda, Tsutomu Sato
    TECTONOPHYSICS 650 53 - 64 2015年05月 [査読有り][通常論文]
     
    The Oman ophiolite is one of the best preserved sections of oceanic crust and upper mantle worldwide, and consists of multiple massifs that lie along more than 400 km of the Arabian coast. In the northernmost massifs, the oceanic crust preserves a record of polygenetic magmatism from mid-ocean ridge to subduction-related stages. The lherzolites and clinopyroxene (Cpx)-rich harzburgites of the Fizh block are located a few tens to a hundred meters above the metamorphic sole of the ophiolite and the geochemistry of these Cpx-rich peridotites provides evidence of a genetic link between oceanic crust and mantle. These Cpx-rich peridotites contain olivine with a restricted range of forsterite contents (90-91), but variable Cr-spinel Cr# (Cr/(Cr + Al) atomic ratio) values (0.12-0.33), suggesting that these Cpx-rich peridotites have undergone variable degrees of melt extraction. Cpxs within the Cpx-rich peridotites have chondrite-normalised trace element variation patterns that slope either gently or steeply between the heavy rare earth elements (REEs) and the middle REEs ((Sm/Yb)(N) = 0.08-0.55, where N chondrite-normalised) and are enriched in highly incompatible elements such as Rb, Ba and Nb. This Cpx chemistry can be explained by a polygenetic evolution whereby an initial 4-12% of melt was extracted from the depleted mantle source before this mantle was metasomatised by interaction with fluids derived from dehydration of the metamorphic sole during subduction initiation and obduction. A comparison between Nd-143/Nd-144 versus Sm-147/Nd-144 for Cpx in the Fizh basal Cpx-rich peridotites and a mineral-whole rock Sm-Nd isochron for a gabbro from the same massif suggests a genetic link between crustal and mantle rocks in this area. In addition, Cpxs within the basal Cpx-rich peridotites have highly variable Sr isotopic compositions that are indicative of a significant contribution of seawater from the metamorphic sole, originally derived from subducted oceanic crustal material. (C) 2014 Elsevier B.V. All rights reserved.
  • Takeshi Matsunaga, Takahiro Nakanishi, Mariko Atarashi-Andoh, Erina Takeuchi, Katsunori Tsuduki, Syusaku Nishimura, Jun Koarashi, Shigeyoshi Otosaka, Tsutomu Sato, Seiya Nagao
    JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY 303 2 1291 - 1295 2015年02月 [査読有り][通常論文]
     
    In order to solve difficulties in collection of river suspended solids (SS) such as frequent observations during stochastic rainfall events, a simple passive collection system of SS has been developed. It is composed of sequentially connected two large-scale filter vessels. A portion of river water flows down into the filter vessels utilizing a natural drop of streambed. The system enable us to carry out long-term, unmanned SS collection. It is also compatible with dissolved component collection. Its performance was validated in a forested catchment by applying to radiocesium and stable carbon transport.
  • Ryo Nishimoto, Qianqian Zhu, Takafumi Miyamoto, Tsutomu Sato, Xuefei Tu, Apichaya Aneksampant, Masami Fukushima
    JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL 396 84 - 89 2015年01月 [査読有り][通常論文]
     
    A biomimetic catalyst, iron(III)-tetrakis(N-methylpyridinium-4-yl)porphyrin (FeTMPyP), was loaded into montmorillonite (Mt) and pillared clay (Pi). The catalytic activities of the prepared catalysts for the decolorization of Acid Orange 7 (AO7) in the absence and presence of,humic acid (HA), a major component of waste water, were compared. Turnover frequencies (TOFs) for the FeTMPyP-loaded Pi (6.7-9.4 h(-1)) were larger than those for the FeTMPyP-loaded Mt (2.9-3.3 h(-1)), while decolorization for the FeTMPyP-loaded Mt was inhibited in the presence of HA (TOFs of 1.3-2.1 h(-1)). These results can be attributed to the fact that the large expansion in basal spacing for the Mt permitted the catalyst to be eluted and HA to be inserted into the Mt layer. However, the levels of catalyst elution and the inhibition of AO7 decolorization by HA were significantly suppressed in the case of the FeTMPyP-loaded Pi catalyst, which was prepared using smaller OH/Al and Al/Mt ratios. These results indicate that the Pi is more suitable support far the FeTMPyP catalyst than the Mt. (C) 2014 Elsevier B.V. All rights reserved.
  • Using Fe–Mn binary oxide three-dimensional nanostructure to remove arsenic from aqueous systems
    Lei, M, Qin, P, Peng, L, Ren, Y, Sato, T, Zeng, Q, Yang, Z, Chai, L
    Water Science and Technology: Water Supply 15 2 516 - 524 2015年 [査読有り][通常論文]
  • Dung Viet Pham, Munehide Ishiguro, Ha Thu Thi Tran, Tsutomu Sato
    SOIL SCIENCE AND PLANT NUTRITION 60 3 356 - 366 2014年06月 [査読有り][通常論文]
     
    Soil dispersion induces soil erosion and colloidal leaching. Nutrients are lost at the same time and this causes water contamination. Phosphate is an essential element for living organisms. Because phosphate influences soil dispersion and it is an important limited resource, this influence must be evaluated well in order to diminish negative effects on soil structure. In this paper, we firstly evaluated the influence of phosphate sorption on soil dispersion by calculating repulsive potential energy between soil particles. Ferralsol, which is a typical soil in rainy tropical regions, was used as the material. The dispersion-flocculation phenomena were investigated with absorbance of soil suspension under different pH, phosphate adsorption and electrolyte concentration in an Na-NO3-PO4 system. The repulsive potential energy was calculated based on the diffuse double layer theory and the measured zeta potential. We indicated that the measured absorbance increased with the increase of the repulsive potential energy. The repulsive potential energy increased with increasing phosphate sorption up to about 5 to 20 mmol kg(-1) at all pH, and it induced the soil dispersion, because phosphate sorption increased the negative charge of the soil. After its peak, it decreased with increasing phosphate sorption because the electrolyte concentration increased and the electrolyte screened the electric field near the soil surface. The repulsive potential energy also increased with increasing pH because of the increase of the negative charge of the soil. Even at low pH, after a certain amount of phosphate sorption, the soil dispersed due to the increase of repulsive potential energy, although the soil flocculated before phosphate application. Because the soil dispersion causes soil and phosphorus loss, the influence of soil pH and phosphate sorption on the soil dispersion should be considered for good soil management.
  • Oda, C, Walker, C, Chino, D, Ichige, S, Honda, A, Sato, T, Yoneda, T
    Applied Clay Science 93-94 62 - 71 2014年05月 [査読有り][通常論文]
     
    Na-montmorillonite (Na(+)Mt) dissolution in a 0.3 mol dm(-3) NaOH solution has been investigated at a pH of 12 at 70 degrees C using a combination of flow-through and batch-type experiments to constrain a predictive geochemical model. The flow-through dissolution experiments were conducted in a dispersed system (initial water/solid ratio = 1000 cm(3) g(-1)) with varying concentrations of Si and Al to derive a Na(+)Mt dissolution rate as a non-linear function of the Gibbs free energy of reaction, Delta G(r,mont). This rate equation was used to simulate the batch-type Na(+)Mt reaction experiments conducted in a coagulated system (initial water/solid ratio = 20 cm(3) g(-1)) in order to examine the applicability of the Delta G(r,mont) rate equation to higher AGnmont conditions and to understand the effect of secondary mineral precipitation on the dissolution rate. The model simulation of the batch-type experiment adopting the empirical rate equations of Na Mt dissolution and secondary mineral analcime precipitation was able to reproduce the measured changes in the amount of dissolved Na Mt and concentrations of Si and Al in solution. The results showed that the empirical rate equation of Na Mt dissolution determined in the far from equilibrium dispersed system was applicable to the coagulated system over a higher AGnmont range and that the concentrations of Si and Al in the batch experiment were controlled by the precipitation of analcime. This implies that the precipitation of secondary minerals will strongly influence the rate of Na+Mt dissolution in the coagulated system. The effects of secondary mineral precipitation on the montmorillonite (Mt) dissolution rate will be, therefore, important in the high density, low water/solid system such as the intended bentonite buffer to be used as the primary barrier in a purpose built repository for the geological disposal of nuclear waste. (C) 2014 Elsevier B.V. All rights reserved.
  • 大竹 翼, 鈴木 陵平, 山田 亮一, 申 基澈, 昆 慶明, 佐藤 努
    日本地球化学会年会要旨集 61 8 - 8 日本地球化学会 2014年 
    本研究では，黒鉱鉱床のような大規模塊状硫化物鉱床の形成要因と当時の海洋環境の関係性をレアアースパターンと鉄安定同位体比を用いて調べた。黒鉱形成後に堆積した鉄に富む化学堆積岩には、レアアースパターンがCeの負異常を示し，また大きな鉄の同位体分別を示すものが存在することから，当時の海洋は酸化還元環境に関して成層化していたと考えられる。このことは，大規模塊状硫化物鉱床の形成において還元的な海洋環境が重要な要因の一つであることを示唆している。
  • 鈴木 啓三, 佐藤 努, 米田 哲朗
    粘土科学討論会発表論文抄録 58 78 - 79 日本粘土学会 2014年
  • 福原 直基, 佐藤 努, 大竹 翼
    粘土科学討論会発表論文抄録 58 116 - 117 日本粘土学会 2014年
  • Fukushima M, Okabe R, Nishimoto R, Fukuchi S, Sato T, Terashima, M
    Applied Clay Science 87 136 - 141 2014年01月 [査読有り][通常論文]
     
    Humic substances have natural surfactant characteristics and have a relatively high affinity for pentachlorophenol (PCP). However, humic substances cannot be loaded into bentonite (Bent) via intercalation because of their larger size. In the present study, a humin-like substance (HuLS) was prepared by polycondensation reactions of humic precursors, such as glycine and catechol, and the product was loaded into Bent. XRD patterns showed that the basal spacing, calculated from the montmorillonite peak, for the HuLS-Bent complex was larger than that for Bent itself, indicating that the intercalation of HuLS was successful. The adsorption capabilities of PCP were evaluated from adsorption isotherms at pH 4.0, 5.5 and 6.5. At all pH values, the linear adsorption coefficients of PCP, K-d (L kg(-1)), for the HuLS-Bent complex (37 at pH 6.5, 247 at pH 5.5 and 804 at pH 4.0) were significantly larger than those for Bent itself (not determined at pH 6.5,40 at pH 5.5 and 94 at pH 4.0). These results show that the adsorption capabilities of PCP can be enhanced by loading HuLS onto Bent. In addition, the K-d values for Bent and the HuLS-Bent complex were found to be pH-dependent, in that the K-d value decreased with increasing pH. Because of the pK(a) for PCP (4.75), more than 90% of the PCP was present as the anionic form at pH 5.5 and 6.5. In addition, the values for the Zeta potentials for Bent and the HuLS-Bent complex remained negative at pH 2-12 and decreased with increasing pH. It thus appears that electrostatic repulsion between the anionic form of PCP and the adsorbents can affect the adsorption capabilities. (C) 2013 Elsevier B.V. All rights reserved.
  • フィリピン国・ルソン島北西部に分布するザンバレスオフィオライトで生成されたアルカリ溶液との反応によって変質されたベントナイトの地球化学的・鉱物化学的特性
    藤井直樹, 山川稔, 鹿園直建, 佐藤努
    地質学雑誌 120 361 - 375 2014年 [査読有り][通常論文]
  • Xiaoji Liu, Atsushi Asai, Tsutomu Sato, Einstine Opiso, Tsubasa Otake, Tetsuro Yoneda
    WATER AIR AND SOIL POLLUTION 224 3 1442 - 1455 2013年03月 [査読有り][通常論文]
     
    The release of anionic nuclides such as I-129 from underground nuclear waste disposals is of great environmental concern due to its long half-life and high mobility in alkaline environments. The leachability of iodide is largely dependent on the sorption capacity of various Ca-bearing minerals such as ettringite, hydrocalumite, and calcium silicate hydrate (C-S-H) which are common hydration products of cement materials. Moreover, the pore water chemistry of cement materials is dominated by Si, Al, and Ca during the initial stage of weathering, and the ratios of the ions present vary much depending on the source materials. Examining the mineral phases generated in Si-Al-Ca systems with respect to different ratios of Si, Al, and Ca and their interaction with iodide is important to better understand the sorption behavior of iodide in nuclear waste disposal facilities. In this study, the mineral synthesis in Si-Al-Ca systems was conducted under alkaline conditions at ambient temperature, and the sorption behavior of iodide with the mineral phases was investigated during and after the mineral formation. The results showed that portlandite, C-S-H, stratlingite (CASH), hydrocalumite, gibbsite, and amorphous compounds were precipitated from the systems, depending on the Si, Al, and Ca ratios. The K-d values of iodide were greatly affected by the Ca content and relatively high Ca-containing phases such as hydrocalumite, C-S-H, CASH, and portlandite showed high iodide retention capacity. Hence, ensuring the formation of these secondary minerals by modification of the chemical composition of cement materials could assist in safety design of nuclear waste disposals.
  • Takeshi Matsunaga, Jun Koarashi, Mariko Atarashi-Andoh, Seiya Nagao, Tsutomu Sato, Haruyasu Nagai
    SCIENCE OF THE TOTAL ENVIRONMENT 447 301 - 314 2013年03月 [査読有り][通常論文]
     
    Effect of intense rainfall on the distribution of Fukushima-accident-derived Cs-137 in soil was examined. Inventories and vertical distributions of Cs-137 in soils were determined at 15 locations (including croplands, grasslands, and forests) in Fukushima city in the post-rainy season, approximately 4.5 months after the accident, and were compared with those in the pre-rainy season determined in our former study. The Cs-137 inventory levels scarcely changed between points in time spanning the first rainy season after the accident. Moreover, the majority of Cs-137 remained stored in the aboveground vegetation and in the upper 5 cm of soil layer at undisturbed locations in the post-rainy season. A more quantitative analysis with the characterization of the vertical profile of Cs-137 using the relaxation length confirmed that the vertical profile was almost unchanged at most locations. Accordingly, it is concluded that rainfall during the rainy season had a limited effect on Cs-137 distribution in the soil, indicating the very low mobility. Chemical extraction of Cs-137 from selected soil samples indicated that Cs-137 in the soil was barely water soluble, and even the fraction extracted with I M ammonium acetate was only approximately 10%. This further supports the low mobility of Cs-137 in our soils. Soil mineralogical analyses, which included the identification of clay minerals, suggested that smectite and mica could lower the exchangeable fraction of Cs-137. However, no direct relationship was obtained between mineral composition and Cs-137 retention in the upper soil layer. In contrast, positive correlations were observed between Cs-137 extractability and soil properties such as pH, organic matter content, finer-sized particle content, and cation-exchange capacity. These results suggest that the mineralogical effect on the firm fixation of Cs-137 on soil constituents may be masked by the non-specific adsorption offered by the physicochemical properties of the soils. (C) 2013 Elsevier B.V. All rights reserved.
  • Ryo Nishimoto, Shigeki Fukuchi, Guangxia Qi, Masami Fukushima, Tsutomu Sato
    COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS 418 117 - 123 2013年02月 [査読有り][通常論文]
     
    Carbonated furnace steel slag is effective in enhancing polycondensation reactions of humic precursors such as quinones, amino acids and saccharides. To obtain more detailed information concerning the nature of the catalytic sites on the surface of slag, a pristine slag sample was treated with HNO3, HF and NH2OH to alter the surface states. The catalytic activities for the formation of humic-like dark-colored polymers were significantly decreased for the samples treated with HNO3 or HF compared to untreated slag. Because substantial amounts of iron were eluted as the result of the HNO3 and HF treatments, the minerals remaining on the surface of steel slag were characterized by XRD and SEM, and the results were compared with untreated slag. XRD patterns indicated the significant decrease in Fe(III) oxide content, including magnetite and hematite, as the result of the HNO3 and HF treatment. In addition, when untreated slag was reacted with humic precursors, the hematite and magnetite were largely eluted as a result of the reaction. These results support the conclusion that Fe(III)-oxides on the surface of steel slag, such as hematite and magnetite, serve as catalytic sites for enhancing catalytic activity for the formation of humic-like dark colored-polymers from humic precursors. (C) 2012 Elsevier B.V. All rights reserved.
  • 上田 麻衣, 中林 亮, 木嶋 達也, 佐藤 努, 米田 哲朗, 大竹 翼, 小田 治恵
    粘土科学討論会発表論文抄録 57 90 - 91 日本粘土学会 2013年
  • 鈴木 啓三, 佐藤 努, 米田 哲朗
    粘土科学討論会発表論文抄録 57 58 - 59 日本粘土学会 2013年
  • 岡橋 東子, 西内 亨, 佐藤 努, 大竹 翼, 米田 哲朗
    粘土科学討論会発表論文抄録 57 156 - 157 日本粘土学会 2013年
  • 伊藤 健一, 宮原 英隆, 氏家 亨, 武島 俊達, 横山 信吾, 中田 弘太郎, 鈴木 伸一, 鈴木 正哉, 佐藤 努, 八田 珠郎, 山田 裕久
    粘土科学討論会発表論文抄録 57 0 72 - 73 日本粘土学会 2013年 [査読無し][通常論文]
  • 佐々木正司, 佐藤努, 川崎康一, 高柳和弘
    Journal of MMIJ : journal of the Mining and Materials Processing Institute of Japan 129 1 29 - 35 The Mining and Materials Processing Institute of Japan 2013年 [査読有り][通常論文]
     
    Si dissolution rate and mechanism of the ferro nickel slag with different mixing ratios of scallop shell and cooling rates have been investigated to apply ferro nickel slag as soil improvement agent. Slag with slow cooling rate was consisted of crystalline materials such as forsterite and enstatite. On the other hand, the slag with rapid cooling rate was amorphous material. Different constituent crystalline materials were obtained by addition of scallop shell. After addition of 30wt% the scallop shell, Ca-bearing crystalline materials such as monticellite, akermanite, wollastonite and augite were generated in the molten slag. The results obtained by batch dissolution experiment and SEM/EDX observation are summarized as follows.
    (1) The amorphous slag has a faster Si dissolution rate than crystalline slag. However, Si dissolution rate of the crystalline slag become faster after addition of scallop shell. Si dissolution rate of the molten ferro nickel slag after addition of 30wt% scallop shell has the same with that of the amorphous slag with rapid cooling rate.
    (2) Ca-bearing crystalline materials such as monticellite, akermanite, wollastonite and augite were easily dissolved than Mg-bearing materials such as forsterite and enstatite which were originally contained in the slag with slow cooling rate.
    (3) Among the crystalline materials in the slag, dissolution of the part consisted mainly of monticellite were distinguished. It was followed by wollastonite, akermanite and augite. Marked dissolution did not observed in the part consisted mainly of forsterite and enstatite.
    (4) Difference in dissolution behavior of the crystalline materials was due to the Ca content and degree of silica tetrahedron polymerization.
    (5) Release of the nutrient elements such as Si and Mg can be promoted by the selection of rapid cooling rate and addition of scallop shell as Ca source in the production of slag.
  • Sylvain Grangeon, Francis Claret, Catherine Lerouge, Fabienne Warmont, Tsutomu Sato, Sohtaro Anraku, Chiya Numako, Yannick Linard, Bruno Lanson
    Cement and Concrete Research 52 31 - 37 2013年 [査読有り][通常論文]
     
    Four calcium silicate hydrates (CSH) with structural calcium/silicon (Ca/Si) ratios ranging from 0.82 ± 0.02 to 0.87 ± 0.02 were synthesized at room temperature, 50, 80, and 110 C. Their structure was elucidated by collating information from electron probe micro-analysis, transmission electron microscopy, extended X-ray absorption fine structure spectroscopy, and powder X-ray diffraction (XRD). A modeling approach specific to defective minerals was used because sample turbostratism prevented analysis using usual XRD refinement techniques (e.g. Rietveld analysis). It is shown that CSH with Ca/Si ratio of ~ 0.8 are structurally similar to nano-crystalline turbostratic tobermorite, a naturally occurring mineral. Their structure thus consists of sheets of calcium atoms in 7-fold coordination, covered by ribbons of silicon tetrahedra with a dreierketten (wollastonite-like) organization. In these silicate ribbons, 0.42 Si per bridging tetrahedron are missing. Random stacking faults occur systematically between successive layers (turbostratic stacking). Layer-to-layer distance is equal to 11.34 Å. Crystallites have a mean size of 10 nm in the a-b plane, and a mean number of 2.6-2.9 layers stacked coherently along the c* axis. © 2013 Elsevier Ltd.
  • 中林亮, 木嶋達也, 塚田康元, 佐藤努, 大竹 翼, 金子勝比古, 米田哲朗
    粘土科学 52 1 9 - 22 一般社団法人 日本粘土学会 2013年 [査読有り][通常論文]
     
    Dissolution rates of montmorillonite in bentonite under hyperalkaline conditions have been obtained to evaluate the long-term performance of engineered barriers for radioactive waste disposal. The saturation state of pore water with respect to montmorillonite in bentonite has been demonstrated as an important factor controlling montmorillonite dissolution rate. Pore water chemistry including the saturation state may be significantly affected by the dissolution of accessory minerals in bentonite. The bentonite "Kunigel V1", which is being considered for use in radioactive disposal barriers in Japan, actually contains a large amount (〜50 %) of accessory silica minerals, such as chalcedony and quartz. Dissolution of the silica minerals may inhibit the dissolution of montmorillonite in the bentonite by increasing the silica concentration and hence the saturation state with respect to montmorillonite in the pore water. Therefore, the objectives of this study are to examine the dissolution kinetics of the silica minerals and the effect of dissolved silica on the dissolution of montmorillonite in a compacted bentonite using X-ray computed tomography (CT) and geochemical modeling. Advective alteration experiments of a compacted bentonite (Kunigel V1) with a dry density of 0.3 Mg/m^3 was conducted with 0.3M NaOH solution at 70℃ for 360 days. X-ray CT images, which were taken every 10 days, showed that the volume of a light colored material decreased as the interaction between the bentonite and hyperalkaline-fluid progressed during the experiments. This is attributed to the dissolution of accessory silica minerals in the bentonite. XRD analyses of altered bentonite after the experiments identified that the accessory mineral was mainly chalcedony. The kinetic data for dissolution of chalcedony was obtained by developing the methodology to quantify the volume of accessory minerals in the CT images. These results showed that chalcedony was almost completely dissolved in the area close to the fluid input within 80 days. The geochemical transport model consistent with the experimental results indicates that the pore water in the bentonite became near saturation with respect to montmorillonite due to the dissolution of silica minerals in bentonite, inhibiting the dissolution of montmorillonite in bentonite. The model also indicates that the inhibition of montmorillonite dissolution will not be sustained beyond the experimental duration under the same experimental conditions. However, a compacted bentonite with higher dry density such as 1.6 Mg/m^3, where diffusion is the dominant mass transport mechanism, has been considered for use in actual radioactive disposal barriers in Japan. In the much more compacted bentonite system, dissolution of montmorillonite will be inhibited for a much longer term. Therefore, it is important to consider the dissolution behavior of silica minerals to sufficiently evaluate the long-term performance of bentonite as a component of engineered barriers for radioactive waste disposal.
  • 鉄との相互作用による緩衝材への変質影響評価：影響要因に関する解析的検討
    中林亮, 木嶋達也, 塚田康元, 佐藤努, 大竹 翼, 金子勝比古, 米田哲朗
    原子力バックエンド研究 20 39 - 52 2013年 [査読有り][通常論文]
  • 佐藤努
    セラミックス 47 11 859-863 - 875 日本セラミックス協会 2012年11月01日 [査読無し][通常論文]
  • Kazuya Morimoto, Sohtaro Anraku, Jun Hoshino, Tetsuro Yoneda, Tsutomu Sato
    JOURNAL OF COLLOID AND INTERFACE SCIENCE 384 1 99 - 104 2012年10月 [査読有り][通常論文]
     
    Complexation reactions of environmentally important inorganic anions such as nitrate, chloride, sulfate, arsenate, and phosphate on the surface of hydrotalcite-like compounds (HT) were investigated to understand the role of HT in the immobilization of hazardous anions in an alkaline environment. The effects of surface complexation reactions on the solid state properties of HT were also evaluated to understand their stability. Synthetic HT was used for the adsorption and post-adsorption experiments. The obtained adsorption isotherms showed that the order of selectivity of HT for anions was NO3 < Cl < - SO4 << AsO4 < PO4. To distinguish the adsorption mechanisms (inner-sphere complexes or outer-sphere complexes) of these anions, zeta potential measurements and infrared absorption spectroscopic analysis were performed. The results indicated that NO3 and Cl were adsorbed as diffuse ions on the outer surfaces of the HT, while SO4 formed outer-sphere complexes with a strong electrostatic interaction. Moreover, AsO4 and PO4 formed inner-sphere complexes via a ligand substitution reaction on the HT surfaces. And it was suggested that oxyanions with low ionic potential, such as AsO4 and PO4, had a tendency to form inner-sphere complexes with the HT surfaces. The formation of inner-sphere complexes shifted the isoelectric point and the surface charge of the HT. Furthermore, the solubility of the HT was reduced by the inner-sphere complexes with PO4 and AsO4. It was revealed, that the formation of inner-sphere complexes on the HT surfaces contributed to the stabilization of the HT, as well as a decrease in the mobility of these anions. (C) 2012 Elsevier Inc. All rights reserved.
  • S. Fukuchi, M. Fukushima, R. Nishimoto, G. Qi, T. Sato
    CLAY MINERALS 47 3 355 - 364 2012年09月 [査読有り][通常論文]
     
    To enhance the catalytic activities of zeolites for the polycondensation reactions of humic precursors, Fe was loaded into a zeolite via an ion-exchange reaction and the resulting product was subjected to calcination at 773 K. Two types iron-loaded zeolites were prepared using one equivalent (Fe-Z-1) and 10-equivalents (Fe-Z-10) of Fe2+ to the cation-exchange capacity of a natural zeolite from Niki town (Hokkaido, Japan). X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) spectra showed that the Fe(II) that was originally loaded into the cation-exchange sites in the zeolite became oxidized to a Fe(111) ionic species during the preparation. The catalytic activities of each zeolite were evaluated, based on the degree of darkening for reaction mixtures containing catechol, glycine and glucose as model humic precursors. The catalytic activities of Fe-Z-1 and Fe-Z-10 were higher than that for an untreated zeolite, and increased with the amount of Fe in the zeolite.
  • Jun Koarashi, Mariko Atarashi-Andoh, Takeshi Matsunaga, Tsutomu Sato, Seiya Nagao, Haruyasu Nagai
    SCIENCE OF THE TOTAL ENVIRONMENT 431 392 - 401 2012年08月 [査読有り][通常論文]
     
    The Fukushima Dai-ichi nuclear power plant accident in Japan, triggered by a big earthquake and the resulting tsunami on 11 March 2011, caused a substantial release of radiocesium (Cs-137 and Cs-134) and a subsequent contamination of soils in a range of terrestrial ecosystems. Identifying factors and processes affecting radiocesium retention in these soils is essential to predict how the deposited radiocesium will migrate through the soil profile and to other biological components. We investigated vertical distributions of radiocesium and physicochemical properties in soils (to 20 cm depth) at 15 locations under different land-use types (croplands, grasslands, and forests) within a 2 km x 2 km mesh area in Fukushima city. The total Cs-137 inventory deposited onto and into soil was similar (58.4 +/- 9.6 kBq m(-2)) between the three different land-use types. However, aboveground litter layer at the forest sites and herbaceous vegetation at the non-forested sites contributed differently to the total Cs-137 inventory. At the forest sites, 50-91% of the total inventory was observed in the litter layer. The aboveground vegetation contribution was in contrast smaller (<35%) at the other sites. Another remarkable difference was found in vertical distribution of Cs-137 in mineral soil layers: Cs-137 penetrated deeper in the forest soil profiles than in the non-forested soil profiles. We quantified Cs-137 retention at surface soil layers, and showed that higher Cs-137 retention can be explained in part by larger amounts of silt- and clay-sized particles in the layers. More importantly, the Cs-137 retention highly and negatively correlated with soil organic carbon content divided by clay content across all land-use types. The results suggest that organic matter inhibits strong adsorption of Cs-137 on clay minerals in surface soil layers, and as a result affects the vertical distribution and thus the mobility of Cs-137 in soil, particularly in the forest ecosystems. (C) 2012 Elsevier B.V. All rights reserved.
  • Einstine Opiso, Atsushi Asai, Tsutomu Sato, Tetsuro Yoneda, Xiaoji Liu
    WATER AIR AND SOIL POLLUTION 223 6 3471 - 3483 2012年07月 [査読有り][通常論文]
     
    The utilization and disposal of alkaline waste materials such as slag and coal fly ash as cement aggregates and raw materials in cement manufacturing can pose environmental and health hazards because these waste materials usually contain elevated concentration of toxic elements. This study examined the possibility of controlling the pore water chemistry of these waste materials in order to induce the secondary mineral formation of Mg-bearing minerals as major sorbing solids for oxyanions during the utilization and disposal of alkaline wastes. The formation of Mg-bearing minerals was examined at ambient temperature and alkaline pH conditions in the Mg-Si-Al system. The interaction of Mg-bearing minerals with oxyanions using arsenate as an analog was examined during and after mineral formation. The results revealed that the generated Mg-bearing mineral phases were smectite and brucite in Mg-Si system and hydrotalcite and serpentine in Mg-Si-Al system. Moreover, hydrotalcite, serpentine, brucite, and smectite phases formed under low Si ratio showed high sorption capacity for arsenate, but only high Al content hydrotalcite and serpentine showed substantial irreversible fraction of sorbed arsenate. Hence, the generation of these kinds of hydrotalcite and serpentine phases as scavengers for oxyanions must be considered during the utilization and disposal of alkaline wastes.
  • 鈴木啓三, 佐藤努, 米田哲朗
    粘土科学 50 3 162-174 - 174 一般社団法人 日本粘土学会 2012年03月30日 [査読無し][通常論文]
     
    The viscosity of aqueous montmorillonite suspensions is affected by many factors, most notable among them include the soluble salt content and composition of exchangeable cations. However, difference in the viscosity of these suspensions remained even at almost identical soluble salt and exchangeable cation compositions. Because of these, the authors made this research based on the following hypothesis: the determining factor for the viscosity of aqueous montmorillonite suspensions is the aspect ratios of montmorillonite particles. Eight montmorillonite samples from Yamagata-Japan, Wyoming-USA and Gujart-India, having wide range of viscosity and aspect ratio, were used. In the experiments, the de-carbonated and Na-exchanged samples in addition to the untreated samples, both purified from bentonite suspension, were utilized. Surface area of basal planes and heights of 100 montmorillonite particles randomly-selected from the untreated samples were measured using AFM. The surface area of the basal planes was converted to the diameter of an equivalent circle. The aspect ratio was then calculated by dividing the diameter of the obtained equivalent circle with the height of the particle. The calculated values of the aspect ratio were at 260-380, 190-210 and 129 for the montmorillonites sampled from Yamagata, Wyoming and Gujarat, respectively. The aspect ratios of some Na-exchanged montmorillonite samples were also determined from the viscosity of diluted suspensions. The values of the aspect ratio obtained using this different method showed good agreement with the results by AFM measurement. This means that montmorillonite particles are suspended in water without folding or bending. For Na-exchanged samples, aspect ratio of montmorillonite particles and viscosity of aqueous suspensions showed good correlation (R^2=0.96). Using Simha's and Einstein's equations, the reason why the aspect ratio is the determining factor for the viscosity of aqueous montmorillonite suspensions could be explained as follows: in the aqueous suspensions, montmorillonie particles are rotating with Brownian movement of water molecules and occupying an apparent volume of sphere having diameter equivalent to the aspect ratio (nm). Apparent volume fraction of montmorillonite, which is calculated by multiplying the apparent volume of the montmorillonite particle and the number of particles in a 1ml suspension, is controlled by the aspect ratio. Because the aspect ratio affects numerically on the order of cube power to the apparent volume fraction of montmorillonite, while the number of particles in suspension affects only on the order of single power, in consideration of Einstein's equation. Montmorillonite that have large aspect ratios even with less number of particles will occupy a large apparent volume fraction in suspension and will have high viscosity. In contrast, montmorillonite with a smaller aspect ratio and large number of particles will occupy a smaller apparent volume fraction and the suspension will have low viscosity. Thus, the determining factor for the viscosity of aqueous montmorillonite suspensions is the aspect ratio of montmorillonite particles. Because this study was made using 8 montmorillonite samples having wide range of aspect ratio and viscosity, we believe that the conclusion obtained is universal.
  • 伊藤健一, 宮原英隆, 氏家亨, 武島俊達, 横山信吾, 中田弘太郎, 永野哲志, 佐藤努, 八田珠郎, 山田裕久
    日本原子力学会和文論文誌 11 4 255 - 271 2012年 [査読無し][通常論文]
     
    In the radiation dosimetry of radiocesium in Iitate, Fukushima, the level of radiocesium around the environment did not exceed the criteria in liquid phases such as puddle water, but was distributed in solid phases such as some soil types and organic matter. On the other hand, retting of the cut bamboo grass and hemlock fir in water allowed the release of radiocesium, about 230 Bq/kg exceeding the criteria for a bathing area. The flow-thru test using zeolite showed the removal of radiocesium from the liquid phase. The wet classification test was performed for 3 types of radiocesium-contaminated soil. According to the results of wet classification, radiocesium was detected and its level exceeded the cropping restriction level in almost all classified particle fractions. The decontamination effect of wet classification on radiocesium contamination was smaller than that on heavy metal contamination. Specifically, the wet classification could not induce volume reduction. Accordingly, preprocessing and intermediate treatments such as dispersion or attrition by vibration or mixing in the wet classification process were devised and examined as improved processing techniques. As a result, the effectual volume reduction of the radiocesium-contaminated soil was confirmed by adding an intermediate process such as the surface attrition in the vibrator. © 2012 Atomic Energy Society of Japan, All Rights Reserved.
  • Arsenic pollution in groundwater at Kandal province, Cambodia
    B. Pich, T. Yoneda, T. Sato
    Proc. of the 4th Regional Conference on Geological Engineering 46 - 52 2012年 [査読有り][通常論文]
  • Sorption of pentachlorophenol to organo-clay complexes prepared by polycondensation reactions of humic precursors.
    Masami Fukushima, Ryo Okabe, Ryo Nishimoto, Shigeki Fukuchi, Tsutomu Sato, Motoki Terashima
    In: “Functions of Natural Organic Matter in Changing Environment” Proceeding Papers of The 16th Meeting of the International Humic Substances Society 299 - 301 2012年 [査読有り][通常論文]
  • 熱水指標としての層状ケイ酸塩鉱物の資源探査への応用について
    米田哲朗, 木工裕史, 松本 晃, 高橋亮平, 佐藤 努
    平成24年度資源・素材学会春季大会講演集（企画発表） 361 - 362 2012年 [査読無し][通常論文]
  • Adsorption and co-precipitation behavior of fluoride onto Mg-bearing minerals in Si-Al-Mg mineral system at hyperalkaline conditions
    Liu, X, Sato, T, Opiso, E, Yoneda, T
    Clay Science 16 49 - 57 2012年 [査読有り][通常論文]
  • 小田治恵, 本田明, 高瀬博康, 小曽根健嗣, 佐々木良一, 山口耕平, 佐藤努
    粘土科学 51 2 34 - 49 一般社団法人 日本粘土学会 2012年 [査読有り][通常論文]
     
    The maximum dose of ionizing radiation from the geological disposal of TRU wastes will likely be controlled by poorly sorbing soluble radionuclides, such as I-129. Proposed repository designs for the geological disposal of TRU wastes envisage the use of an engineered barrier composed of a bentonite buffer to limit the migration of such radionuclides by impeding groundwater flow. Cementitious materials will inevitably be used for waste packaging, in filling and adding structural integrity to the repository. Using cementitious materials, however, is problematic because they produce highly alkaline leachates which have the potential to cause a complex series of coupled changes in the porewater chemistry, mineralogy and, ultimately, the mass transport properties of the bentonite buffer. To elucidate the consequences of these coupled changes, reactive-transport model analyses have been conducted for bentonite alteration test cases with the use of different combinations of secondary minerals that will likely form in the bentonite buffer. A dissolution rate equation of smectite (a key component of bentonite) applicable to pH 7-13 and 25-80 ℃ was proposed and used in the reactive-transport model analyses. It was found that the amount of dissolved smectite at the center of the bentonite buffer was smaller and those in the vicinity of the cement interface was larger when thermodynamically metastable secondary minerals mainly precipitated as compared with the precipitation of stable phases. The calculated temporal and spatial changes of kinetic smectite dissolution were interpreted as a consequence of the changes in Gibbs free energy and porewater chemistry. Furthermore, the bentonite porewater chemistry was also affected by the stoichiometry and thermodynamic stability of the secondary minerals and the kinetics of smectite dissolution. Except in the close proximity of the cement interface, it was found that regardless of the choice of secondary minerals, the effective diffusion coefficient and hydraulic conductivity remained largely unchanged after 100,000 years.
  • 佐々木正司, 川崎康一, 佐藤努
    青森県産業技術センター工業部門事業報告書 2010 66  2011年12月28日 [査読無し][通常論文]
  • 佐藤 努
    粘土科学 50 2 26 - 32 日本粘土学会 2011年12月25日 [査読無し][通常論文]
     
    The Fukushima Dai-ichi nuclear disaster is a series of equipment failures, nuclear fuel meltdowns, and releases of the fission products and feasible neutron activated nuclides to the environment at the Fukushima Nuclear Power Plant, following the 9.0 magnitude east-Japan earthquake and the ensuing tsunami on 11 March 2011. As the result of radionuclide releases, the soils, drinking water, foods, water in swimming pool, building wall, road and forest in Fukushima were widely contaminated with the radionuclides, especially ^<137>Cs. Although it is urgent to figure out how radioactive material...
  • A. Miura, S. Fukuchi, R. Okabe, M. Fukushima, M. Sasaki, T. Sato
    CLAY MINERALS 46 4 637 - 648 2011年12月 [査読有り][通常論文]
     
    Polycondensation reactions between amino acids and phenols are one of the pathways for the formation of humic substances, and clay minerals are able to catalyse these reactions. To investigate the catalytic power of allophane, an allophane fraction (ALF) was separated from weathered pumice (WP) that contained imogolite as an impurity by taking advantage of differences in sedimentation velocity. The iron content in the separated ALF was increased by up to 3.0% compared to that in the starting WP (1.3%), and the ALF was further treated with sodium dithionate and citric acid (ALF-DC) to remove the iron. The catalytic powers of WP, ALF and ALF-DC were evaluated, based on the degree of darkening of reaction mixtures from polycondensation reactions between catechol and tryptophan, model compounds for precursors of humic substances. The catalytic power for ALF was significantly higher than the corresponding values for WP and ALF-DC. This can be attributed to the high iron content of the ALF, which serves as a Lewis acid that can enhance nucleophilic reactions which occur during the polycondensation reactions.
  • Nicolas C. M. Marty, Jordi Cama, Tsutomu Sato, Daisuke Chino, Frederic Villieras, Angelina Razafitianamaharavo, Jocelyne Brendle, Eric Giffaut, Josep M. Soler, Eric C. Gaucher, Christophe Tournassat
    GEOCHIMICA ET COSMOCHIMICA ACTA 75 20 5849 - 5864 2011年10月 [査読無し][通常論文]
     
    The effect of pH and Gibbs energy on the dissolution rate of a synthetic Na-montmorillonite was investigated by means of flow-through experiments at 25 and 80 degrees C at pH of 7 and 9. The dissolution reaction took place stoichiometrically at 80 degrees C, whereas at 25 degrees C preferential release of Mg over Si and Al was observed. The TEM-EDX analyses (transmission electronic microscopy with quantitative chemical analysis) of the dissolved synthetic phase at 25 degrees C showed the presence of newly formed Si-rich phases, which accounts for the Si deficit. At low temperature, depletion of Si concentration was attributed to incongruent clay dissolution with the formation of detached Si tetrahedral sheets (i.e., alteration product) whereas the Al behaviour remains uncertain (e. g., possible incorporation into Al-rich phases). Hence, steady-state rates were based on the release of Mg. Ex situ AFM measurements were used to investigate the variations in reactive surface area. Accordingly, steady-state rates were normalized to the initial edge surface area (11.2 m(2) g(-1)) and used to propose the dissolution rate law for the dissolution reactions as a function of Delta G(r) at 25 degrees C and pH similar to 9: r(mol m(-2) s(-1)) = 3.82 x 10(-12) [1 - exp(-8.23 x 10(-10)vertical bar Delta G(r)/RT vertical bar(5.47))]. (C) 2011 Elsevier Ltd. All rights reserved.
  • Ryo Okabe, Akitaka Miura, Masami Fukushima, Motoki Terashima, Masahide Sasaki, Shigeki Fukuchi, Tsutomu Sato
    CHEMOSPHERE 83 11 1502 - 1506 2011年06月 [査読無し][通常論文]
     
    An allophanic soil (AS) catalyzed the formation of dark-colored polymers via polycondensation reactions between catechol and glycine. The organic carbon content of the AS was increased from 0.16% to 1.3%, indicating that some of the dark-colored polymers had been adsorbed to the AS. The characteristics of the dark-colored polymers adsorbed on the AS were similar to those of a humin that is not extractable with an aqueous alkaline solution. Such a humin-like substance (HuLS) was separated from the AS by treatment with a mixture of HF and HCl. The HuLS and humic acid-like substance (HaLS), comprising the acid-insoluble fraction in the reaction mixture, were characterized by elemental analysis, size exclusion chromatography, pyrolysis-GC/MS and (13)C NMR. However, the structural features of HaLS and HuLS had many points in common. These results suggest that HuLS-AS can be regarded as an organo-clay complex formed by the strong adsorption of HaLS to the AS. The adsorption of pentachlorophenol (PCP) to AS and HuLS-AS was examined at pH 5.5. At this pH, the zeta potential of the HuLS-AS showed a negative value. It would, therefore, be expected that pentachlorophenolate anions would adsorb with difficulty to HuLS-AS because of electrostatic repulsion. Nevertheless, the adsorption coefficient for PCP to HuLS-AS, as estimated by the Freundlich isotherm, was seven times larger than that for AS. These results show that HuLS, when adsorbed on the AS surface, has the capability to enhance the adsorption of PCP. (c) 2011 Elsevier Ltd. All rights reserved.
  • UENO KENICHI, SUYAMA TADAHIRO, ISHIDERA TAKAMITSU, SATO TSUTOMU
    Clay science 15 2 89 - 102 日本粘土学会 2011年06月 [査読無し][通常論文]
     
    In the Japanese high-level waste (HLW) repository design, compacted bentonite and carbon steel overpack are the main components of the engineering barrier system. The possibility that the chemical and physical properties of the compacted bentonite might change after interaction with corrosion products of the carbon steel has been noted. Experimental validation of the interaction of smectite in compacted bentonite as simulated in the HLW repository system is still very limited. This study focuses on smectite and corrosion product interaction and Fe migration behavior in compacted bentonite s...
  • Tetsushi Nagano, Nobuyuki Yanase, Yukiko Hanzawa, Morio Takada, Hisayoshi Mitamura, Tsutomu Sato, Hirochika Naganawa
    WATER AIR AND SOIL POLLUTION 216 1-4 153 - 166 2011年03月 [査読無し][通常論文]
     
    In order to evaluate fixation potential of schwertmannite for fluvial transport of various toxic elements, we examined bottom precipitates and stream waters collected from the rivers contaminated with acid mine drainage (AMD), which arose from the abandoned Nishinomaki mine (Shimonita, Gunma, Japan). Mineralogical and morphological observations revealed that schwertmannite was the main mineral of the precipitates. The affinity of various toxic ions to schwertmannite was evaluated on the basis of (1) apparent solid-liquid partition coefficients (K (d)'s) between precipitates and stream waters, (2) coprecipitation behaviors during schwertmannite formation in a laboratory test, and (3) consideration on coprecipitation processes using partial charge model (PCM). As a result, oxyanions of V, As, Mo and Sb, K (d)'s of which were relatively large (> 10(4) (ml g(-1))), were considered to be immobilized by schwertmannite precipitates. A laboratory test also demonstrated that these ions except Mo coprecipitated with schwertmannite. In addition, partial charges and average electronegativities predicted on the basis of PCM suggested that the oxyanions of V, As, Mo, and Sb could create stable inner sphere complexes with schwertmannite embryos, which results in their high affinity to schwertmannite. On the other hand, cationic ions of Mn, Cu, Zn, Sr, Cs, and U, K (d)'s of which were relatively small (< 10(4) (ml g(-1))), were thought to have a tendency to flow downstream without uptake by schwertmannite precipitates. All these results suggested that schwertmannite has high fixation potential for fluvial transport of various toxic oxyanions in AMD-contaminated rivers.
  • PICH BUNCHOEUN, YONEDA TETSURO, SATO TSUTOMU
    Clay science 15 1 53 - 59 日本粘土学会 2011年03月 [査読無し][通常論文]
     
    The high arsenic content in groundwaters of Kandal province, Cambodia has threatened about 1 million people with tens of them being at risk to arsenicosis. In this context, this study aims to investigate the removal of arsenic from Kandal groundwater by utilizing naturally available laterite from Kampong Cham province in order to obtain safe drinking waters for the people. The laterite samples were characterized with XRD, XRF, zeta potential analyzer, and surface area analyzer. Batch adsorption experiment of As(V) onto laterite was conducted under ambient temperature as a function of adsorb...
  • 安楽 総太郎, 星野 純, 松原 勇武, 福士 圭介, 佐藤 努, 米田 哲朗
    粘土科学討論会発表論文抄録 55 74 - 75 日本粘土学会 2011年
  • 鈴木 啓三, 佐藤 努, 米田 哲朗
    粘土科学討論会発表論文抄録 55 48 - 49 日本粘土学会 2011年
  • 中林 亮, Elakneswaran Yogaraiah, 千野 大輔, 佐藤 努, 米田 哲朗, 小田 治恵, 金子 勝比古
    粘土科学討論会発表論文抄録 55 46 - 47 日本粘土学会 2011年
  • Arsenic Mineralogy of some hydrothermal ore deposits in abandoned mine area of southwestern Hokkaido, Japan
    T. Yoneda, T. Bando, T. Sato
    Proc. of the 5th Int. Workshop and Conference on Earth Resources Technology 14 - 16 2011年 [査読有り][通常論文]
  • 西内 亨, 岡本 浩紀, 伊藤 健一, 佐藤 努, 米田 哲朗
    粘土科学討論会発表論文抄録 55 0 194 - 195 日本粘土学会 2011年 [査読無し][通常論文]
  • 柴田 真仁, 坂本 浩幸, 佐藤 努
    日本原子力学会和文論文誌 = Transactions of the Atomic Energy Society of Japan 10 2 91 - 104 日本原子力学会 2011年 [査読無し][通常論文]
     
    The interaction between compacted bentonite and hardened cement was evaluated. Cement-bentonitecement-layered test specimens, after infiltrated with water, were subjected to various analyses. The EPMA analysis of the cross sections of the specimens indicated a homogeneous distribution of Ca leached from the cement paste in the bentonite. The quantity of Ca in the bentonite was apparently larger than the cation exchange capacity of the bentonite, suggesting the formation of secondary minerals involving Ca. © 2011 Atomic Energy Society of Japan, All Rights Reserved.
  • Y. Elakneswaran, A. Iwasa, T. Nawa, T. Sato, K. Kurumisawa
    CEMENT AND CONCRETE RESEARCH 40 12 1756 - 1765 2010年12月 [査読無し][通常論文]
     
    The main objective of this investigation is to describe the interaction between cement hydrates and electrolyte solution to understand multi-ionic transport in cementitious materials. A surface complexation model in PHREEQC including an electrostatic term is used to simulate the ionic adsorption on the calcium silicate hydrate (C-S-H) surface. The equilibrium constants for the adsorption of ions on C-S-H surfaces are obtained by fitting experimental data to the model. The adsorption of both divalent and mono-valent cations, and also anions significantly changes the surface charges of hydrated paste. Chloride is being held in a chemical binding as Friedel's salt and bound mainly by the adsorptive action of C-S-H. An integrated modelling approach employing a phase-equilibrium model, a surface complexation model, and a multicomponent diffusion model has been developed in PHREEQC to simulate the multi-ionic transport through hydrated cement paste. It was found that the physical adsorption of ions on C-S-H, the size of pores, and the surface site density of C-S-H govern the rate of penetration of ionic species. Finally, the proposed model has been validated against chloride profiles measured in this study as well as with data available in the literature for hydrated cement paste. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.
  • Nobuyasu Itoh, Shuji Tamamura, Tsutomu Sato, Michio Kumagai
    LIMNOLOGY 11 3 241 - 250 2010年12月 [査読無し][通常論文]
     
    We examined monthly changes in polycyclic aromatic hydrocarbons (PAHs) in sediment trap samples collected from the northern basin of Lake Biwa, Japan, from September 2003 to July 2004 to elucidate the sources of PAHs in the lake. The most abundant concentrations were those of pyrene and fluoranthene, at mu g g(-1) levels throughout the sampling period, with a strong positive relationship (r = 0.996, n = 10, P < 0.01). From the monthly changes in each PAH concentration and their ratios, we suspected two different sources: petroleum sources of lighter PAHs and combustion sources of middle to heavier PAHs. Because pyrene and fluoranthene decreased significantly with time during the sampling period (P < 0.05) and an abnormally high ratio of phenanthrene to anthracene was reported in September 2003, it appears that petroleum was accidentally spilled in September 2003. Although perylene was commonly found at mu g g(-1) levels in the sediment, its concentration was comparable with those of the other PAHs in sediment trap samples. As perylene showed no significant relationship with other PAHs or other indicator molecules, we suspect that the source of perylene was different from those of other PAHs, and the perylene was mainly formed from its precursors after deposition.
  • Shigeki Fukuchi, Akitaka Miura, Ryo Okabe, Masami Fukushima, Masahide Sasaki, Tsutomu Sato
    JOURNAL OF MOLECULAR STRUCTURE 982 1-3 181 - 186 2010年10月 [査読無し][通常論文]
     
    Polycondensation reactions between low-molecular-weight compounds, such as amino acids, sugars and phenols, are crucially important processes in the formation of humic substances, and clay minerals have the ability to catalyze these reactions. In the present study, catechol (CT), glycine (Gly) and glucose (GI) were used as representative phenols, amino acids and sugars, respectively, and the effects of the catalytic activities of natural zeolites on polycondensation reactions between these compounds were investigated. The extent of polycondensation was evaluated by measuring the specific absorbance at 600 nm (E(600)) as an index of the degree of darkening. After a 3-week incubation period, the E(600) values for solutions that contained zeolite samples were 4-10 times greater than those measured in the absence of zeolite, suggesting that the zeolite had, in fact, catalyzed the polycondensation reaction. The humic-like acids (HLAs) produced in the reactions were isolated, and their elemental composition and molecular weights determined. When formed in the presence of a zeolite, the nitrogen contents and molecular weights for the HLAs were significantly higher, compared to the HLA sample formed in the absence of zeolite. In addition, solid-state CP-MAS (13)C NMR spectra and carboxylic group analyses of the HLA samples indicated that the concentration of carbonyl carbon species for quinones and ketones produced in the presence of zeolite were higher than the corresponding values for samples produced in the absence of a zeolite. Carbonyl carbons in quinones and ketones indicate the nucleophilic characteristics of the samples. Therefore, a nitrogen atom in Gly, which serves as nucleophile, is incorporated into quinones and ketones in CT and GI. The differences in the catalytic activities of the zeolite samples can be attributed to differences in their transition metal content (Fe, Mn and Ti), which function as Lewis acids. (C) 2010 Elsevier B.V. All rights reserved.
  • Shuji TAMAMURA, Tsutomu SATO, Yukie OTA, Ning TANG, Kazuichi HAYAKAWA
    Acta Geologica Sinica - English Edition 80 2 185 - 191 2010年09月07日
  • OKAMOTO Hiroki, MORIMOTO Kazuya, ANRAKU Sohtaro, SATO Tsutomu, YONEDA Tetsuro
    Clay Sci 14 5 203-210 - 210 日本粘土学会 2010年09月 [査読無し][通常論文]
     
    To develop a novel remediation for Cu- and Zn-bearing wastewater, the natural attenuation process in Dougamaru abandoned mine at Shimane Prefecture, Japan was investigated. In the Dougamaru abandoned mine, Cu- and Zn-bearing mine drainage was naturally attenuated by formation of green precipitate composed of Cu-bearing layered double hydroxide (LDH), hydrowoodwardite (HW) with chemical formula such as Cu_<0.66>Zn_<0.09>Fe_<0.01>Al_<0.23>(OH)_2(SO_4)_<0.15>・mH_2O. This attenuation was achieved at pH 6.0 with aeration and bacterial respiration and without any neutralization process attributed to the mixing with spring or surface water. The formation of the HW at pH 6 is also confirmed by thermodynamic consideration in this study. The formation process of the HW at the Dougamaru abandoned mine teaches us a novel technology for remediation system with addition of Al ion to wastewater and without employing any extensive chemical treatment processes. From the experiment to check applicability of Cu- and Zn-bearing LDHs to wastewater treatment, HW (Cu-bearing LDH) and zincowoodwardite (ZW; Zn-bearing LDH) were obtained by addition of Al ion to the Cu- and Zn-bearing wastewater from lower pH condition. The improvement of removal efficiency by adding Al ion in Cu-bearing wastewater system was not so clear in the experiment because Cu ion is removed from the synthetic wastewater due to Cu-hydroxyl sulfate precipitation at the experimental condition. On the other hand, the removal efficiencies of Zn ion showed the range from 0 to 30% even at pH 6.0 and improved with increasing initial Al ion content. The experimental results in Zn-bearing wastewater system indicate that the safety remediation of Zn ion can be achieved even at lower pH than 6.0-7.0 by selection of the ZW as a candidate of the solubility-limiting solid phase. Moreover, because of high anion exchange capacity of LDH, the method with addition of Al ion source for the wastewater treatment may also be useful for the treatment of wastewater containing Cu and Zn ions and simultaneously with As, Se, and Sb anions, which shows good performance in terms of anion remediation.
  • E. M. Opiso, T. Sato, K. Morimoto, A. Asai, S. Anraku, C. Numako, T. Yoneda
    MINERALS ENGINEERING 23 3 230 - 237 2010年02月 [査読無し][通常論文]
     
    The release of toxic anions during the chemical weathering of alkaline wastes such as blast furnace slag and coal fly ash presents a serious problem to public health and the environment. This study investigated arsenate sorption behavior onto Mg-bearing minerals formed in the Mg-Si-Al system at alkaline pH conditions in order to understand the safe removal and encapsulation of arsenate by Mg-bearing minerals under such conditions. Sorption experiments were performed during and after mineral formation and leaching tests using phosphate bearing solution were conducted to understand arsenic association with the minerals. The results revealed that brucite (Mg(OH)(2)), hydrotalcite (Mg(6)Al(2)(CO(3))(OH)(16)center dot 4(H(2)O)) and serpentine (MgSi(2)O(5)(OH)(4)) have high uptake capacity for arsenate. However, arsenic incorporation was only observed during the formation of high Al content hydrotalcite and serpentine minerals and was greatly enhanced at higher temperature. This implies that by controlling pore water chemistry of alkaline wastes with high reactivity, the irreversible fixation of arsenic by Mg-bearing minerals in alkaline conditions can be expected. (C) 2009 Elsevier Ltd. All rights reserved.
  • 宮脇 律郎, 佐野 貴司, 大橋 文彦, 鈴木 正哉, 小暮 敏博, 奥村 大河, 亀田 純, 梅染 卓也, 佐藤 努, 千野 大輔, 弘山 郁織, 山田 裕久, 田村 堅志, 森本 和也, 上原 誠一郎, 八田 珠郎
    粘土科学 48 4 158 - 198 日本粘土学会 2010年01月18日 [査読無し][通常論文]
  • N. Fujii, C. A. Arcilla, M. Yamakawa, C. Pascua, K. Namiki, T. Sato, N. Shikazono, W. R. Alexander
    Proceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM 2 41 - 50 2010年 [査読有り][通常論文]
     
    Bentonite is one of the safety-critical components of the engineered barrier system for the disposal concepts developed for many types of radioactive waste. However, bentonite - especially the swelling clay component that contributes to its essential barrier functions - is unstable at high pH. To date, results from laboratory tests on bentonite degradation have been ambiguous as the reaction rates are so slow as to be difficult to observe. As such, a key goal in this project is to examine the reaction of natural bentonites in contact with natural hyperalkaline groundwaters to determine if any long-term alteration of the bentonite occurs. Ophiolites have been identified as sources of hyperalkaline groundwaters that can be considered natural analogues of the leachates produced by some cementitious materials in repositories for radioactive waste. At the Zambales ophiolite in the Philippines, widespread active serpentinisation results in hyperalkaline groundwaters with measured pH values of up to 11.7, falling into the range typical of low-alkali cement porewaters. These cements are presently being developed worldwide to minimise the geochemical perturbations which are expected to result from the use of OPC-based concretes (see Kamei et al., this conference, for details). In particular, it is hoped that the lower pH of the low-alkali cement leachates will reduce, or even avoid entirely, the potential degradation of the bentonite buffer which is expected at the higher pH levels (12.5 and above) common to OPC-based concretes. During recent field campaigns at two sites in the Zambales ophiolite (Mangatarem and Bigbiga), samples of bentonite and the associated hyperalkaline groundwaters have been collected by drilling and trenching. At Mangatarem, qualitative data from a 'fossil' (i.e. no groundwater is currently present) reaction zone indicates some alteration of the bentonite to zeolite, serpentine and CSH phases. Preliminary reaction path modelling suggests that the zeolites could have been produced as a product of smectite reaction in the hyperalkaline groundwaters. Although not included in this calculation to date, the CSH phases identified are completely consistent with reaction of clays with hyperalkaline groundwaters, as seen at other sites worldwide. At the Bigbiga site, an active hyperalkaline groundwater/bentonite reaction zone (at the base of the bentonite deposit) has recently been identified and a drilling campaign is planned for late autumn 2010. © 2010 by ASME.
  • Sohtaro Anraku, Kazuya Morimoto, Tsutomu Sato, Tetsuro Yoneda
    PROCEEDINGS OF THE 12TH INTERNATIONAL CONFERENCE ON ENVIRONMENTAL REMEDIATION AND RADIOACTIVE WASTE MANAGEMENT 2009, VOL 2 849 - 854 2010年 [査読有り][通常論文]
     
    In Japanese transuranic (TRU) waste disposal facilities, (129)I is the most important key nuclide for the long-term safety assessment. Thus, the Kd values of I to natural minerals are important factor in the safety assessment. However, the degradation of cement materials in the repositories can produce high pH pore fluid which can affect the anion transport behavior. Therefore, it is necessary to understand the behavior of anions such as I(-) under the hyperalkaline conditions. The natural hyperalkaline spring water (pH>11) in the Oman ophiolite is known to be generated from the partly serpentinized peridotites. The spring water is characteristically hyperalkaline, reducing, low-Mg, Si and HCO(3)(-), and high-Ca, while the river water is moderately alkaline, oxidizing, high-Mg and HCO(3)(-). The mixing of these spring and river water resulted in the formation of secondary minerals. In the present study, the naturally occurring hyperalkaline conditions near the springs in Oman were used as natural analogue for the interaction between cement pore fluid and natural Mg-HCO(3)(-) groundwater. The present aim of this paper is to examine the conditions of secondary mineral formation and the anion uptake capacity of these mineral in this system. Water and precipitate samples were collected from the different locations around the spring vent to identify the effect of mixing ratios between spring and river water on mineral composition and water-mineral distribution coefficient of various anions. On-site synthesis was also carried out to support these data quantitatively. Aragonite was observed in all precipitates, while calcite, brucite and Mg-Al hydrotalcite-like compounds (HTlc) were also determined in some samples. Calcite was observed only closed to the springs. At locations far from the springs, calcite formation was inhibited due to high-Mg fluid from river water. Brucite was observed from the springs with relatively low-Al concentration and HTlc was the opposite. During the formation of the minerals at the mixing points, HCO3- in the river water was fixed as carbonate minerals such as in aragonite and calcite while H(3)SiO(4)(-) in the river water was dominantly fixed into interlayers and surfaces of HTlc. Iodine in spring and river water was mainly fixed in aragonite. Therefore, the uptake I(-) by secondary minerals can be expected at hyperalkaline conditions as observed at Oman hyperalkaline springs.
  • 鉱床探査における熱水指標としての層状ケイ酸塩鉱物の重要性，緑泥石－スメクタイト系鉱物の化学組成と構造特性の適用性
    米田哲朗, 木工裕史, 佐藤努
    資源・素材2010（福岡）,企画発表講演資料A 205 - 208 2010年 [査読無し][通常論文]
  • 西南北海道の二つのタイプの浅熱水性金鉱床における砒素の鉱物学と溶出特性の比較
    坂東知哉, 米田哲朗, 畑山恵, 佐藤努, 伊藤俊彦
    資源・素材2010（福岡）,企画発表講演資料A 209 - 212 2010年 [査読無し][通常論文]
  • F. Claret, C. Lerouge, T. Laurioux, M. Bizi, T. Conte, J. P. Ghestem, G. Wille, T. Sato, E. C. Gaucher, E. Giffaut, C. Tournassat
    GEOCHIMICA ET COSMOCHIMICA ACTA 74 1 16 - 29 2010年01月 [査読無し][通常論文]
     
    Iodine is one of the most problematic radioisotopes in the context of nuclear waste geological disposal due to its high mobility. Considerable effort has been dedicated to the measurement of its potential retardation during diffusive transport leading to conflicting results, from no retardation to significant retardation, leading in turn to considerable debate. The present study aims at providing new insights into this aspect of the iodine problem by careful quantification of iodine reservoirs in the Callovian-Oxfordian (Cox) clay rock taken here as model material for these studies. The present study confirmed the ubiquitous presence of iodine at 1-5 mg kg(-1) level in the Cox clayey formation. The iodide concentration level in the pore-water is also confirmed at a value in the range similar to 20-40 mu mol L(-1), i.e. higher than the expected range of radio-iodine concentration in the far-field of the storage. Surprisingly, most of the iodine was found not to be associated with organic matter but rather in an inorganic form associated with carbonate minerals. This result has potentially significant implications for the fate of radio-iodine. In undisturbed far-field conditions, most natural iodine would not be accessible for isotopic exchange with radioactive iodine, reducing the effective Kd to negligible values. During laboratory experiments, good monitoring of the geo-chemical parameters (at least the Eh, pH, P(CO2), [Ca] and [Mg]) is mandatory to avoid iodine-bearing carbonate precipitation and to enable rigorous interpretation of the iodide diffusion/retention experiments. (C) 2009 Elsevier Ltd. All rights reserved.
  • Einstine Opiso, Tsutomu Sato, Tetsuro Yoneda
    JOURNAL OF HAZARDOUS MATERIALS 170 1 79 - 86 2009年10月 [査読有り][通常論文]
     
    Pollution caused by boric acid and toxic anions such as As(V), Cr(VI) and Se(VI) is hazardous to human health and environment. The sorption characteristics of these environmentally significant ionic species on allophane-like nanoparticles were investigated in order to determine whether allophane can reduce their mobility in the subsurface environment at circum-neutral pH condition. Solutions containing 100 or 150 mmol of AlCl(3)center dot 6H(2)O were mixed to 100 mmol of Na(4)SiO(4) and the pH were adjusted to 6.4 +/- 0.3. The mineral suspensions were shaken for 1 hand incubated at 80 degrees C for 5 days. Appropriate amounts of As, B, Cr and Se solutions were added separately during and after allophane, precipitation. The results showed that As(V) and boric acid can be irreversibly fixed during co-precipitation in addition to surface adsorption. However, Cr(VI) and Se(VI) retention during and after allophane precipitation is mainly controlled by surface adsorption. The structurally fixed As(V) and boric acid were more resistant to release than those bound on the surface. The sorption characteristics of oxyanions and boric acid were also influenced by the final Si/Al molar ratio of allophane in which Al-rich allophane tend to have higher uptake capacity. The overall results of this study have demonstrated the role of allophane-like nanoparticles and the effect of its Si/Al ratio on As, B, Cr and Se transport processes in the subsurface environment. (C) 2009 Elsevier B.V. All rights reserved.
  • Chie Kawaragi, Tetsuro Yoneda, Tsutomu Sato, Katsuhiko Kaneko
    ENGINEERING GEOLOGY 106 1-2 51 - 57 2009年05月 [査読無し][通常論文]
     
    Bentonite is a very attractive raw material as a compacted clay liner at general waste disposal sites and also as a buffer material at radioactive waste disposal sites. It has been considered that the permeability of bentonite, the most important index for evaluating barrier materials, is closely related to its microstructure. Recent studies in geological material science show that X-ray computerized tomography (X-ray CT) is a very powerful too[ for the study on microstructure and hydro-osmotic phenomena (e.g. Wong and Wibowo [Wong, R., Wibowo, R., 2000. Tomographic evaluation of air and water flow patterns in soil column. Geotech. Test. J. 23, 413-422]). Permeability tests and micro X-ray CT observations of Wyoming bentonite were performed to describe the relationship between microstructure and permeability of the bentonite used as a barrier material. Two types of samples, compacted bentonite-quartz sand mixtures and raw bentonite ores, were used in this study. The X-ray CT observations of the bentonite-quartz sand mixtures show that 'vacant pores' and 'bentonite-water complexes' of the bentonite samples after water permeation are distinguishable in X-ray CT images, and that the micro-structural differences are closely relating to the sample permeability, and depend on the mixing and saturation conditions. Permeability tests and X-ray CT observations of the bentonite ore samples show that the permeability and the microstructure are independent to the sedimentary texture developed within the ore samples. In addition, it is characteristic that the bentonite ore samples with micro-cracks show low hydraulic conductivity, comparable to the compacted powder bentonite, implying that cracks in the sample are filled with 'bentonite-water complexes' formed after permeation. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.
  • 森本 和也, 佐藤 努, 米田 哲朗
    粘土科学 48 1 9 - 17 The Clay Science Society of Japan 2009年04月10日 [査読無し][通常論文]
     
    Complexation reactions of environmentally important oxyanions such as nitrate (NO_3), sulfate (SO_4), phosphate (PO_4), and arsenate (AsO_4) on brucite (Mg(OH)_2) surfaces were investigated to understand the role of brucite in immobilization of hazardous oxyanions at hyperalkaline environment. The impacts by surface complexation reactions on solid state properties of brucite were also evaluated. Synthetic brucite was used for the adsorption and post-adsorption experiments as a starting material. In the adsorption experiments, the synthesized brucite was reacted with various oxyanion solutions with concentration up to 100μmol/L for 12 hours at 25 degrees Celsius. The obtained adsorption isotherms showed that brucite had the selectivity for oxyanions during adsorption with the affinity sequence being NO_3) of the brucite was also determined by zeta potential measurements. The pH_ of brucite with NO_3 and SO_4 was close to 13.0. On the other hand, pH_ of the brucite with PO_4 was approximately 10.7 and that of the brucite with AsO_4 was close to 10.2. These results indicate that NO_3 and SO_4 presented as diffuse ions on the brucite surfaces. In contrast, PO_4 and AsO_4 formed inner-sphere complexes by a ligand-substitution reaction on the brucite surfaces. It took notice of influences on the solubility of brucite caused by the formation of inner-sphere complexes. The saturation indexes (SI) of brucite with PO_4 and AsO_4 have a range from 0.24 through 0.39, and were lower than that of sample without the oxyanions. The decreasing in SI indicates that the solubility of brucite is decreasing by the inner-sphere complexes with PO_4 and AsO_4. Therefore, it implies that the adsorption reactions of PO_4 or AsO_4 induced the notable decreasing in the solubility of brucite itself. It is revealed that the formation of inner-sphere complexes on the brucite surfaces contributes to the stabilization of brucite as well as the decreasing mobility of these oxyanions. Consequently, the adsorption mode of anions on brucite should be determined by chemical properties inherent in the elements; oxyanions with low ionic potential have a tendency to form inner-sphere complexes with brucite surfaces.
  • Shuji Tamamura, Tsutomu Sato, Yukie Ota, Yasuaki Aota, Kenji Kashiwaya, Michio Kumagai
    WATER AIR AND SOIL POLLUTION 198 1-4 297 - 306 2009年03月 [査読無し][通常論文]
     
    Seasonal deposition fluxes of polycyclic aromatic hydrocarbons (PAHs) in the North Basin of Lake Biwa were investigated by monthly collecting sediment trap samples through a year from July 2003. Average deposition flux of total PAHs was 75 ng cm(-2) year(-1), similar to those for other rural area. Deposition fluxes of PAHs did varied seasonally. In the vertical mixing period of the lake, late autumn to early spring, the fluxes of less volatile PAHs were enhanced while those for volatile PAHs were not. The size difference of particles associated with volatile and less volatile PAHs caused the seasonal variation of the fluxes. Oil discharge from water delivery equipments may contribute the fluxes of volatile PAHs in summer to autumn.
  • 森本 和也, 安楽 総太郎, 佐藤 努, 米田 哲朗
    日本地球化学会年会要旨集 56 103 - 103 日本地球化学会 2009年 
    オマーンオフィオライトにおいて、モホ遷移帯付近よりpH11を超える高アルカリ泉の湧出が認められている。本研究では、高アルカリ泉の組成と湧出口付近で地表水との混和により生成している白色の沈殿物の組成を明らかにし、それらの生成過程について考察した。白色の沈殿物は全てアラゴナイトやカルサイトといった炭酸カルシウムを多く含んでいた。このほかMg含有鉱物であるブルーサイトやハイドロタルサイトを特徴的に含む試料があった。ハイドロタルサイトの生成には、高アルカリ泉中のAl濃度が大きく寄与していた。またIR・SEM-EDX分析より、ハイドロタルサイトが陰イオンとしてケイ酸イオンを含有していることが示唆された。高アルカリ泉の進化過程において、ケイ酸イオンを含有するハイドロタルサイトの生成がSiおよびMgのシンクとして重要な役割を果たしていることが推察された。
  • Susumu Kurosawa, Hiroyuki Sakamoto, Kiyofumi Nitta, Chiya Numako, Kazuko Haga, Masahito Shibata, Tsutomu Sato, Toshiyuki Nakazawa, Hitoshi Owada
    Materials Research Society Symposium Proceedings 1193 489 - 496 2009年 
    Chemical conditions and mass transport properties of engineered barrier systems in TRU waste facilities would change with time due to the interaction of cement/bentonite materials. (TRU waste' is one of categories of the radioactive wastes and contains a significant amount of alpha-emitting transuranic nuclides. In some countries, these wastes are classified into the Intermediate Level Waste (ILW).) Previous numerical model analyses to assess the long-term performance of engineered barrier systems in TRU waste repositories predicted to form Calcium Silicate Hydrate (C-S-H) species at the interface between the cementitious and bentonite materials. If C-S-H precipitates in the bentonite side of the boundary, mass transport in the bentonite buffer decreases and mineralogical alterations are expected to be restricted for a long period. The evidence of C-S-H precipitation in the bentonite side, however, still has not been identified in the former experimental studies. To improve the reliability of numerical analyses, immersion experiments were performed using contact samples of cementitious and bentonite materials, and X-ray absorption fine structure (XAFS) analysis was carried out to detect C-S-H precipitation at the contacting interface. Precipitation of C-S-H was confirmed from the obtained XAFS spectra. This result is one of the evidences to show the validity of the current numerical model analyses, which suggests that the bentonite buffer performance as an engineered barrier would be kept over a long period. © 2009 Materials Research Society.
  • Arsenic Immobilization by Mg-bearing Minerals at Alkaline pH Condition: Lessons Learnt from Natural Processes
    E.M. Opiso, T. Sato, K. Morimoto, S. Anraku, C. Numako, T. Yoneda
    Proc. of the 3rd International Workshop and Conference on Earth Resources and Technology CD-ROM 2009年 [査読有り][通常論文]
  • Arsenate incorporation onto allophone
    E.M. Opiso, T. Sato, T. Yoneda
    Proc. of the 1st Regional Conference on Geo-Disaster Mitigation and Waste Management in ASEAN 78 - 84 2009年 [査読有り][通常論文]
  • XRDリートベルト法による鉱物定量分析の探査への適用について
    米田哲朗, 坂東知哉, 佐藤 努
    資源・素材札幌2009 講演資料集 (A6) 187 - 190 2009年 [査読無し][通常論文]
  • 高田 盛生, 福士 圭介, 佐藤 努, 米田 哲郎
    粘土科学 47 4 255 - 260 The Clay Science Society of Japan 2008年12月28日 [査読無し][通常論文]
     
    Adsorption and post-adsorption characteristics of different oxyanions such as P, Cr, As and Se onto schwertmannite were investigated in order to understand the role of schwertmannite in acid mine drainage, and its performance and safety assessment in remediation system. Synthetic schwertmannite was used for the adsorption and post-adsorption experiments as a starting material. In the adsorption experiments, the starting material was reacted with various oxyanion solutions such as Na_2HPO_4, Na_2CrO_4・4H_2O, Na_2HAsO_4・7H_2O and Na_2SeO_4 with concentration up to 2.0mM at around pH 3.9. Dominant chemical species of the oxyanions in the experimental condition were thermodynamically calculated as H_2PO_4^-, HCrO_4^-, H_2AsO_4^- and SeO_4^<2-> by Geochemist's Workbench. The obtained adsorption isotherms showed that the schwertmannite has selectivity for oxyanions during adsorption with the affinity sequence being H_2AsO_4^->H_2PO_4^->HCrO_4^->SeO_4^<2->. This sequence corresponds to the sequence of decreasing ionic potential of the anions, which suggest that the observed selectivity of schwertmannite could not be attributed to the electrostatic interaction between the oxyanions and schwertmannite. It is known that oxyanions with low ionic potential have a tendency to form inner-sphere complexation with mineral surfaces. Therefore, the observed order of oxyanion retention may correspond to the sequence in affinity for the inner-sphere complexation on schwertmannite. This is also supported by the results of zeta potential measurement, which showed greater decrease of zeta potential after H_2AsO_4^- and H_2PO_4^- adsorption compared to other onyanions. In post-adsorption experiments (aging experiments), transformation to goethite was observed in X-ray diffraction patterns for the schwertmannite containing oxyanions with lower selectivity such as SeO-4^<2-> and SO_4^<2-> while there is no change in X-ray diffraction patterns of schwertmannite with H_2AsO_4^- and H_2PO_4^- even after 556 hours. Desorption of SeO_4^<2-> and SO_4^<2-> was observed prior to the transformation, although most of H_2AsO_4^- and H_2PO_4^- were retained onto schwertmannite. The desorption of oxyanions therefore resulted in the transformation of schwertmannite to goethite. Oxyanions with higher adsorption affinity, i.e., lower ionic potential, have a greater stabilizing effect on schwertmannite structure, although ordinary schwertmannite with SO_4^<2-> is metastable and easily transforms to goethite.
  • 伊藤 健一, 福士 圭介, 橋本 晃一, 田中 小満, 池田 穂高, 佐藤 努, 米田 哲朗
    Journal of MMIJ : journal of the Mining and Materials Processing Institute of Japan 124 8 519 - 528 社団法人 資源・素材学会 2008年08月25日 [査読無し][通常論文]
     
    The acid mine drainages (AMD) are treated by neutralization with the two problems: (1) an enormous expenditure; and (2) a discharge of neutralization sludge. In this context, as a case study, a novel remediation method was applied for AMD at Horobetsu mine. The schwertmannite is generated by iron-oxidizing bacteria with Fe<SUP>2+</SUP> and SO<SUB>4</SUB><SUP>2-</SUP> in acidic mine waters. Its efficiency in As uptake through sorption has been documented in the natural attenuation in Nishinomaki. This study demonstrates the advantages and feasibility of utilizing schwertmannite as a novel re...
  • 佐藤 努, 福士 圭介, 米田 哲朗
    日本地球化学会年会要旨集 55 339 - 339 日本地球化学会 2008年 
    近年、世界各地で問題となっている有害無機陰イオンによる地下水・土壌汚染は、多岐にわたる分野で解決が望まれている緊急課題である。有害無機陰イオンに限らず、土壌や地層などの天然における化学物質の挙動を解析する場合には、その移動媒体である天然水に溶出した物質がどのように存在し、どのようにして構成物質表面に濃縮され蓄積されるか（収着されるか）について記述し予測することが必要となる。そこで発表では、その記述や予測に不可欠となる代表的な無機陰イオン種のスペシエーションや代表的な鉱物への吸着・収着挙動についてまとめるとともに、それらを踏まえたうえで、天然における有害無機陰イオンのマネージメントの方策について議論する。
  • 佐藤 努, 浅井 篤史, 安楽 総太郎, 森本 和也, Opiso Einstine, 沼子 千弥, 米田 哲朗
    日本鉱物科学会年会講演要旨集 2008 159 - 159 日本鉱物科学会 2008年 
    近年、世界各地で問題となっている有害無機陰イオンによる地下水・土壌汚染は、多岐にわたる分野で解決が望まれている緊急課題である。有害無機陰イオンに限らず、土壌や地層などの天然における化学物質の挙動を解析する場合には、その移動媒体である天然水に溶出した物質がどのように存在し、どのようにして構成物質表面に濃縮され蓄積されるか（収着されるか）について記述し予測することが必要となる。そこで発表では、その記述や予測に不可欠となる代表的な無機陰イオン種のスペシエーションや代表的な鉱物への吸着・収着挙動についてまとめるとともに、それらを踏まえたうえで、天然における有害無機陰イオンのマネージメントの方策について議論する。
  • 弘山 郁織, 大田 由貴恵, 佐藤 努, 米田 哲朗
    日本鉱物科学会年会講演要旨集 2008 170 - 170 日本鉱物科学会 2008年 
    様々な研究によって酸化物や粘土鉱物がアミノ酸重合反応において触媒となることがわかっているが、相対湿度によって鉱物表面の活性を変化するという粘土鉱物の固体酸としての特性に着目した研究はない。鉱物の触媒作用の挙動を検証するには鉱物表面の水分をコントロールする必要があり、相対湿度はその役割を担うことができる。このことは鉱物表面でのペプチド生成メカニズム解明の手がかりとなりえる。著者らの研究により相対湿度を制御することによりアミノ酸重合反応に対する鉱物の触媒作用は変化すること、ヘクトライトが最も触媒として効果があることが明らかになった。この触媒作用に対する因子は鉱物の構造ではなく組成であることが示唆された。ヘクトライトは構造にＭｇ－Ｏを持つためペリクレースを用いて相対湿度実験を行い、のＭｇ－Oがアミノ酸重合の触媒部位となっていることが推察された。
  • 木工 裕史, 米田 哲朗, 佐藤 努
    日本鉱物科学会年会講演要旨集 2008 82 - 82 日本鉱物科学会 2008年 
    粘土鉱物の諸特性，たとえば粒径（層厚）や粒径分布は、粘土鉱物生成時の熱水環境と関係する鉱物学的特性の一つとして近年注目される。豊羽地域の熱水系から産するボーリングコア中の緑泥石および雲母鉱物の粒径（層厚）解析を行い、それら特性と環境条件との関連性について検討を行った。ほとんどの試料から、雲母鉱物と緑泥石を確認できた。それら緑泥石は、おおよそ20-30nmの平均層厚の値を示し，深度との一つの明瞭な関係は認められないが，熱水変質による珪化・粘土化が卓越する上部（500m以浅）に比べてプロピライト変質が卓越する下部（600m以深）では深部に向け層厚が厚くなる傾向が認められる。さらに，得られた平均層厚とコア試料の掘削時の検層温度や試料中の流体包有物の均質化温度などの温度データとの関連性を検討した。
  • An application of XRD Rietveld method to the mineral phase quantification of geological materials
    T. Yoneda, K. Sasaki, T. Sato
    Proceedings of the 2nd Int. Workshop and Conference on Earth Resources Technology 2008年 [査読有り][通常論文]
  • 伊藤 健一, 福士 圭介, 橋本 晃一, 田中 小満, 池田 穂高, 佐藤 努, 米田 哲朗
    J. MMIJ 124 8 519 - 528 The Mining and Materials Processing Institute of Japan 2008年 [査読無し][通常論文]
     
    The acid mine drainages (AMD) are treated by neutralization with the two problems: (1) an enormous expenditure; and (2) a discharge of neutralization sludge. In this context, as a case study, a novel remediation method was applied for AMD at Horobetsu mine. The schwertmannite is generated by iron-oxidizing bacteria with Fe2+ and SO42- in acidic mine waters. Its efficiency in As uptake through sorption has been documented in the natural attenuation in Nishinomaki. This study demonstrates the advantages and feasibility of utilizing schwertmannite as a novel remediation method for AMD.
    At first, the drainage and sludge in Horobetsu mine were characterized to investigate the current method. Secondly, the synthesis of schwertmannite and arsenic removal from the drainage were examined. Results of the characterization indicated that the sludge contained much residual calcite and arsenic by adsorption to the ferrihydrite. The calcite, however, may be dissolved with rainwater. After the reaction, pH of the sludge should be increased and then, which presumably causes the desorption of arsenic from the ferrihydrite. On the contrary, schwertmannite, successfully synthesized from Horobetsu mine drainage by pH adjustment to pH 3.5, removed As almost completely from the drainage.
    A novel processing method proposed based on the above results consists of the following procedure: (1) arsenic in AMD is removed by the schwertmannite, process, (2) As-free schwertmannite is spontaneously synthesized from the drainage by pH adjustment to pH 3.5 and iron-oxidizing bacteria, and supplied to (1), and (3) the drainage is neutralized in order to remove sulfate by using the waste concrete. In the above procedure, As-bearing schwertmannite, As-free schwertmannite and gypsum are produced as byproduct. This novel processing method is therefore defined as combination system including the removal of arsenic, iron, and sulfate and the resource recovery from AMD.
  • 鈴木啓三, 佐藤努, 米田哲朗, 榎戸洋之
    粘土科学 46 2 120 - 130 日本粘土学会 2007年06月04日 [査読無し][通常論文]
     
    Montmorillonite samples were obtained from the suspension of Yamagata-bentonite with four purification processes to investigate underlying conditions which cause their viscosity. The samples were also treated repeatedly by 70% 2-propanol solution with different times to prepare the samples with different amounts of water soluble salts. Moreover, the treatments with sodium acetate-acetic acid solution (pH:5.0) and NaCl solution were conducted to dissolve Ca-carbonate minerals and to homo-ionize the samples. Electrical conductivity (relating to the amount of water soluble salts) and viscosity of the montmorillonite suspensions were measured for the samples with different pre-treatments. From the results of measurements, the following conclusions were obtained. 1. Viscosities of the montmorillonite suspension are negatively correlated with their electrical conductivities. Under the higher content of water soluble salts (higher electrical conductivity), viscosity of the samples is lower. 2. In the salt concentration of 2.5 × 10^<-6>〜2.5 × 10^<-4>moll^<-1>, zeta-potentials of the samples are almost constant. 3. Even under the same content of water soluble salts, the obvious difference in viscosity of the samples with four purification processes was observed. The order of viscosity among the samples was not changed even after treatments with sodium acetate-acetic acid solution (pH:5.0) and NaCl solution. Consequently, the difference in the viscosity, therefore, may not arise from the external chemical conditions such as content of water soluble salts and species of exchangeable cation. 4. The observed difference in viscosity among the samples would be attributed to the difference in aspect ratios or particle sizes (sizes in a-b plane) of montmorillonite in the samples with different purification processes.
  • Chelo Supnet Pascua, Mio Minato, Shingo Yokoyama, Tsutomu Sato
    GEOTHERMICS 36 3 230 - 242 2007年06月 [査読無し][通常論文]
     
    A study has been made on the uptake of dissolved arsenic in a recirculation system designed to extract silicates for secondary use from spent (i.e. cooled) geothermal brine. Excess dissolved calcium, due to addition of lime (CaO), favours the precipitation of As-bearing phases in the retrieved materials. Controlling dissolved calcium in a continuous recirculation system is not easy to achieve; arsenic removal prior to precipitation of silicates is expected to be more practical. Predicted and measured arsenic speciation in the spent geothermal brine is dominated by arsenite species that were previously shown to lack affinity with most inorganic sorbents. However, synthetic schwertmannite was able to selectively remove dissolved arsenic without any significant accompanying decrease in silica concentrations. Its use prior to the introduction of spent geothermal brine into the recirculation system will likely make silica retrieval more feasible. (c) 2007 CNR. Published by Elsevier Ltd. All rights reserved.
  • Shuji Tamamura, Tsutomu Sato, Yukie Ota, Xilong Wang, Ning Tang, Kazuichi Hayakawa
    ATMOSPHERIC ENVIRONMENT 41 12 2580 - 2593 2007年04月 [査読無し][通常論文]
     
    Aerosol particles were collected for I year, starting in April 2003, in rural areas of Kanazawa, Ishikawa, Japan to understand the role of Asian dust as a long-range transporter of polycyclic aromatic hydrocarbons (PAHs). Three sampling intervals were designated in this study, namely: (1) Dust period I (March 11-19, 2003); (2) Dust period 2 (March 28, 2003-April 9, 2003); and (3) Dust period 3 (April 9, 2004-April 25, 2004). The Asian dust particles are predominantly in the coarse particle size range (2.1-11 mu m). PAH analyses were performed separately on both the coarse and fine (< 1.1 mu m) particle ranges. Seasonal trends in PAH concentrations for coarse and fine particles showed that the Asian dust particles in Dust period 3 contained significant amounts of less-volatile PAHs such as benzo[a]pyrene (BaP) and benzo[g,h,i]perylene (BghiP). A kinetic model developed in this study shows that almost none of these PAHs would be accumulated on Asian dust particles in the atmosphere, due to their extremely slow adsorption rates. These PAHs would have to originate from PAH-polluted soil particles around industrialized areas. Back trajectory analyses suggest that the Asian dust in Dust period 3 came from loess regions around industrialized areas. This indicates that geologic materials play a significant role in the atmospheric circulation of PAHs. (c) 2006 Elsevier Ltd. All rights reserved.
  • Shunsuke Sakai, Akira Yoshiasa, Hiroshi Arima, Maki Okube, Chiya Numako, Tsutomu Sato
    AIP Conference Proceedings 882 274 - 276 2007年 [査読有り][通常論文]
     
    Local structure around arsenic atoms in K-T boundary clays was studied by As K-edge XAFS spectroscopy. The threshold E0 energy of As and the characterization of the white peak of XANES spectra agree well with the values of As(+5) minerals like Zn2(AsO4)2(OH) 22H2O and CaCu(AsO4)(OH) according to the comparison with several types of arsenic minerals. This indicates that arsenic is in a high oxidation state As(+5) and occupies the AsO4 tetrahedral site of a mineral in K-T boundary clays. © 2007 American Institute of Physics.
  • 佐藤 努, 福士 圭介, 米田 哲朗
    資源・素材学会誌 123 4 132 - 144 社団法人 資源・素材学会 2007年 [査読無し][通常論文]
     
    The contamination of groundwater with dissolved cationic chemical species such as Ni, Cu, Zn, Cd, Hg, and Pb has been an important concern in the past. Dissolved anionic species such as As has received a more important focus due to its prevalence in West Bengal as a toxic contaminant affecting several hundreds of thousands of people. Nitrates and phosphates from excessive use of fertilizers in agriculture and detergents in households are grim reminders of dissolved anion contamination in rural groundwater supplies. Chemical weathering of slag and fly ash recycled as cement materials can rel...
  • 鈴木 啓三, 高木 慎介, 佐藤 努, 米田 哲朗
    粘土科学 46 3 147 - 155 日本粘土学会 2007年 [査読無し][通常論文]
     
    モンモリロナイトが本来有している特性を知るため,山形産ベントナイトを原料として,自然沈降分離,超遠心分離,酢酸-酢酸ナトリウム溶液による脱炭酸塩処理,アルコール水溶液による可溶性塩および土壌有機物の溶解・除去,Na-交換処理などを組み合わせて,可能な限り火雑物を除き,高度に精製した"高精製モンモリロナイト"を試作し,試料のキャラクタリゼーションを行った.HP-Montの特徴は以下のとおりである.1)化学分析,XRD,TG-DTA,CEC,LCの測定などを行った結果,極めて高純度であることが確認できた.トータルの層電荷量は,0.410esu/half unit cellで,この中の約30%が四面体シートに,約70%が八面体シートに分布していた.モンモリロナイトとしては,比較的四面体置換量が大きい.この値が,山形産モンモリロナイトの層電荷を示すと考えて良い.2)微細な石英,土壌有機物などがほぼ完全に除去された結果,HP-Mont粉末は,Com-Mont粉末に比較して色が白く,1%分散液はほぼ無色透明であった.3)HP-Montの水分散液は,濃度1.5%で524mPa・sと極めて高い粘度を示した.この粘度は,Com-Montの4.0%分散液の粘度よりも高い.4)HP-Montの水分散液は,徴酸性を示し,Com-Montのそれと大きく異なっていた.これは,精製過程において炭酸ナトリウム,カルサイトなどがほぼ完全に除去されたためと考えられる.5)HP-Montは,精製の過程で超遠心分離を行っているため,層面方向の大きさは,通常のCom-Montに比してやや小さい.6)HP-Montのゼータ電位は,Com-Montのゼータ電位よりも絶対値がやや大きい.可溶性塩含有量が極めて少ないためと考えられる.
  • Mitsuo Manaka, Nobuyuki Yanase, Tsutomu Sato, Keisuke Fukushi
    GEOCHEMICAL JOURNAL 41 1 17 - 27 2007年 [査読無し][通常論文]
     
    In this study, we investigated the natural attenuation of antimony (Sb) in the drainage water of an abandoned mine. Drainage water, waste rocks, and ocherous precipitates collected from the mine were investigated in terms of their mineralogy and chemistry. The chemistry of the drainage water was analyzed by measuring pH, oxidation-reduction potential (ORP), and electric conductivity on site as well as by inductively coupled plasma mass spectrometry and ion chromatography. As the drainage flowed downstream, the pH decreased rapidly from 7.05 to 3.26 and then increased slowly to 3.50. In a section where the pH increased, ocherous precipitates occur on a drainage water channel. We determined Sb levels in the drainage water, and the distribution of Sb in the mineral phases of waste rocks and precipitates was estimated by means of a sequential extraction procedure. The results of these investigations indicated that Sb, which is generated by the dissolution of stibnite (Sb2S3) and secondary formed Sb minerals in waste rocks, was attenuated by iron-bearing ocherous precipitates, especially schwertmannite, that form over time in the drainage water. The Sb concentrations in the ocherous precipitates were up to 370 mg/kg, whereas the Sb concentrations in the drainage water downstream were below background levels (0.6 mu g/L). Bulk distribution coefficients (K-d) for this Sb adsorption to the precipitates ranges up to at least 10(5) L/kg.
  • Xilong Wang, Tsutomu Sato, Baoshan Xing
    CHEMOSPHERE 65 11 2440 - 2448 2006年12月 [査読有り][通常論文]
     
    Aerosol samples were collected from Kanazawa, Japan to examine the size distribution of 12 elements and to identify the major sources of anthropogenic elements. Key emission sources were identified and, concentrations contributed from individual sources were estimated as well. Concentrations of elements V, Ca, Cd, Fe, Ba, Mg, Mn, Ph, Sr, Zn, Co and Cu in aerosols were determined with ICP-MS. The results showed that Ca, Mg, Sr, Mn, Co and Fe were mainly associated with coarse particles (> 2.1 mu m), primarily from natural sources. In contrast, the elements Zn, Ba, Cd, V, Pb and Cu dominated in fine aerosol particles (< 2.1 mu m), implying that the anthropogenic origin is the dominant source. Results of the factor analysis on elements with high EFCrust values (> 10) showed that emissions from waste combustion in incinerators, oil combustion (involving waste oil burning and oil combustion in both incinerators and electricity generation plants), as well as coal combustion in electricity generation plants were major contributors of anthropogenic metals in the ambient atmosphere in Kanazawa. Quantitatively estimated sum of mean concentrations of anthropogenic elements from the key sources were in good agreement with the observed values. Results of this study elucidate the need for making pollution control strategy in this area. (c) 2006 Elsevier Ltd. All rights reserved.
  • 佐藤努
    J Soc Inorg Mater Jpn 13 325 441-447  2006年11月01日 [査読無し][通常論文]
  • 佐藤 努
    Journal of the Society of Inorganic Materials, Japan : セッコウ・石灰・セメント・地球環境の科学 13 325 441 - 447 無機マテリアル学会 2006年11月01日 [査読無し][通常論文]
  • XL Wang, T Sato, BS Xing
    ENVIRONMENTAL SCIENCE & TECHNOLOGY 40 10 3267 - 3272 2006年05月 [査読無し][通常論文]
     
    Sorption isotherms of pyrene on original and heat-treated wood chars were examined to understand its sorption behavior. Pyrene in single-solute systems had nonlinear isotherms. Polanyi-based dual-domain model fit sorption data well, and the model results showed that the adsorption component dominated pyrene sorption by original char at all aqueous concentrations. In contrast, this adsorption component contributed a much lower fraction to the total sorption by the heat-treated char, and dominated only at low solute concentrations; with increasing concentration, partitioning became a predominant contributor to the total sorption. Competitive effect of four cosolutes, phenanthrene (Phen), benzo[a] anthracene (BaA), 2,2-methylene- bis (4-methyl-6-tert-butylphenol) (MMBP), and phenol on pyrene sorption by original and treated chars was examined to understand the underlying mechanism of competition. Hydrophobicity (adsorbability) and molecular size of competitors played an important role in competition with pyrene by both chars, suggesting the direct competition for sorption sites and pore blockage mechanism. Competitive sorption results indicated that the fate and transport of hydrophobic organic chemicals (e.g., pyrene) could be strongly affected in the presence of coexisting organic contaminants with high hydrophobicity and large molecular size, thereby, enhancing the mobility and leachability of these chemicals.
  • Yohey Suzuki, Tsutomu Sato, Hiroshi Isobe, Toshihiro Kogure, Takashi Murakami
    American Mineralogist 90 8/9 1308 - 1314 2006年 [査読有り][通常論文]
  • 様々な鉄鋼スラグから生成する陰イオン吸着材の生成と安定性
    伊藤亜希子, 佐藤努, 片桐有由未, 湊美緒, 伊藤健一, 米田哲朗
    資源・素材2006（福岡）講演資料集 (C6), 101 - 102 2006年 [査読無し][通常論文]
  • シュベルトマナイトを用いたヒ素汚染土壌不溶化の長期安全評価
    佐藤努, 福士圭介, 高田盛生, 伊藤健一, 池田穂高, 川西琢也, 米田哲朗
    資源・素材2006（福岡）講演資料集 (C6) 95 - 96 2006年 [査読無し][通常論文]
  • シュベルトマナイトを用いたヒ素汚染水や土壌の浄化方法
    伊藤健一, 池田穂高, 福士圭介, 川西琢也, 佐藤努, 米田哲朗
    資源・素材2006（福岡）講演資料集 (C6) 91 - 94 2006年 [査読無し][通常論文]
  • S Tamamura, T Sato, Y Ota, N Tang, K Hayakawa
    ACTA GEOLOGICA SINICA-ENGLISH EDITION 80 2 185 - 191 2006年 [査読無し][通常論文]
     
    The fate of Polycyclic Aromatic Hydrocarbons (PAHs) residing in the atmosphere has received enormous attention in recent years due to their mutagenic and carcinogenic risks on human health. In this context, the stability of pyrene (as a representative PAHs) on quartz, alumina, montmorillonite, kaolinite, humic acid and quartz coated with sorbed humic acid was investigated at controlled relative humidity (RH: i.e. 5% and 30%) without light irradiation in order to detect the presence of catalytic effect of mineral surface on PAHs decomposition. The stability of pyrene was found to depend strongly on the physicochemical properties of the substrates. Quartz showed a strong catalytic effect for the decomposition of pyrene even though it was coated with sorbed humic acid. Pyrene sorbed on montmorillonite and humic acid remained stable during the experimental period (i.e. 3 days). Moisture in the experimental cell also affected the stability of pyrene in particular minerals. Especially, pyrene sorbed on alumina was rapidly decomposed at higher RH. However, there were almost no effect in the case of quartz, kaolinite and humic acid. Depending on the physicochemical properties of aerosols and RH, PAHs associated with minerals in the atmosphere would be decomposed and/or stably reside in the atmosphere.
  • C Pascua, T Sato, G Golla
    ACTA GEOLOGICA SINICA-ENGLISH EDITION 80 2 230 - 235 2006年 [査読無し][通常論文]
     
    Arsenic is usually associated with sulphide minerals formed in the geothermal environment. However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Secondary precipitates that form from the dissolution of the primary sulfides exert a greater influence on arsenic mobility in the geothermal environment. Fe-hydroxides have very good affinity with dissolved arsenate and are stable under most surface oxidizing conditions. Both amorphous silica directly precipitated from geothermal fluids and possibly a kaolinite alteration can host a small significant amount of arsenic. These silicates are also more stable under a wide range of pH and redox conditions.
  • 早川和一, 岩坂泰信, 佐藤努
    環境情報科学 34 3 17-28  2005年11月14日 [査読無し][通常論文]
  • 井上 厚行, 河野 元治, 桑原 義博, 小崎 完, 小峯 秀雄, 佐藤 努, 月村 勝宏
    粘土科学 45 1 31 - 61 The Clay Science Society of Japan 2005年11月11日 [査読無し][通常論文]
  • XL Wang, T Sato, BS Xing
    ENVIRONMENTAL SCIENCE & TECHNOLOGY 39 22 8712 - 8718 2005年11月 [査読有り][通常論文]
     
    Sorption isotherms of pyrene on soils and sediments were examined to understand its sorption behavior. All systems examined exhibited nonlinear sorption. Sorption nonlinearity was found to be a function of the polarity index of soil/sediment organic matter (SOM), suggesting that the degree of condensation of SOM, characterized by its polarity index, was correlated with the sorption behavior of pyrene. The polarity index of SOM could be a new factor for explaining the sorption nonlinearity. The sorption affinity of two soils and two sediments for pyrene increased with decreasing SOM polarity. A higher sorption affinity in the two soils was associated with a higher degree of condensation of SOM compared to that of the two sediments. A displacement test was performed after pyrene sorption using phenanthrene as a displacer. Pyrene was displaced in all systems examined, and nonlinearity became less pronounced after displacement. Such an increase in isotherm linearity implied that sorption site energies became more homogeneous after displacement. Furthermore, the site energy distribution F(E*) derived from the Freundlich model parameters showed that energy reduction of high-energy sites was more significant than that of low-energy sites after displacement. In addition,a decrease in sorption capacity after displacement could be ascribed to the partial depletion of sorption sites by the displacer. The displacement data indicated that the cocontaminant can have potential effects on the fate and bioavailability of anthropogenic organic pollutants sorbed in soils and sediments,thus affecting their exposure risks.
  • XL Wang, T Sato, BS Xing, S Tao
    SCIENCE OF THE TOTAL ENVIRONMENT 350 1-3 28 - 37 2005年11月 [査読無し][通常論文]
     
    Consumption of vegetables and fish contaminated with the heavy metals Cu, Zn, Pb, Cd, Hg, and Cr is the most likely route for human exposure in Tianjin, China. Health risks associated with these heavy metals were assessed based on the target hazard quotients (THQs), which can be derived from concentrations of heavy metals in vegetables and fish consumed in four districts (Dong Li, Xi Qing, Jin Nan, and Bei Chen) and the urban area of Tianjin, China. Individual metal THQ (< 1) values indicate the relative absence of health risks associated with intake of a single heavy metal through consumption of either contaminated vegetables or fish only. However, consumption of both vegetables and fish would lead to potential health risks especially for children, since individual THQs for vegetables and fish would sum up to almost 1. If individual THQs resulting from crops consumption are considered, the health risks would be greater for children since the THQ values will always be > 1. Risk contribution from Cr is minimal compared to the other elements. Hg is the major risk contributor for children in Bei Chen since the THQ contribution amounts to about 45% of the total THQ values due to vegetables and fish consumption. The health risk to adults in Ding Li is ascribed mainly to the intake of Cd by vegetables and fish consumption, which contributes a substantial fraction to the total THQ (about 51%). (c) 2004 Elsevier B.V. All rights reserved.
  • K Fukushi, T Sato
    ENVIRONMENTAL SCIENCE & TECHNOLOGY 39 5 1250 - 1256 2005年03月 [査読有り][通常論文]
     
    Nanoparticles are discrete nanometer-scale assemblies of atoms and have dimensions between those characteristic of ions and those of macroscopic materials. These minerals commonly possess extremely large specific surface areas and surface adsorption capacities for foreign ions. Due to the large specific surface area and large fraction of surface atoms, the natures of nanoparticles are expected to be modified by the adsorption (surface complexation) process. In this paper, we discuss theoretically the stability of nanoparticles that make the surface complex with foreign ions. The principal theoretical assumption is that the surface complexation occurs at the bulk of the nanoparticles, as in a solid solution. The surface complexation affects two aspects of the intrinsic stability of the nanoparticles simultaneously: one is the composition of the nanoparticles; the other is the free energy of formation of nanoparticles, The solubility of hydrous ferric oxide WO) was estimated by using surface complexation modeling coupled with published data of the free energy of formation of the relevant components. The solubility modeling of surface-charged (H+ or OH- sorbed) HFO mechanistically and quantitatively explained the observed nonintegral behavior of the solubility of HFO. solubility modeling of anion (SO42-, PO43- and As (V)) sorption by HFO showed that the sorption process strongly influences the stability of the nanoparticles. This result implies that geochemical modeling leads to the erroneous prediction of a natural system if the effect of the sorption process is not taken into account.
  • XL Wang, T Sato, BS Xing, S Tamamura, S Tao
    JOURNAL OF AEROSOL SCIENCE 36 2 197 - 210 2005年02月 [査読有り][通常論文]
     
    The concentrations of trace metals in aerosols of different sizes in the suburban area of Kanazawa, Japan were determined with inductively coupled plasma mass spectrometry (ICP-MS). The results indicated that, among the anthropogenic elements, the ambient concentration of Zn in the total suspended particles (TSP) was the highest (1386 ng/m(3)) and Cd concentration was the lowest (0.45 ng/m(3)). For the contribution of each particle size fraction to the total metal concentration in aerosols, except for V (33.6%), the "very coarse" aerosol size range (> 11 mum) contributed a small mass fraction (only 4.05-11.7%). While the "coarse fraction" (11-3.3 mum) had the largest mass percentage for most elements. However, the mass percentage of individual metals to the total sum of all investigated metals in each particle size range (from very coarse to very fine) was quite similar, which implied that the coagulation of airborne particles occurred in the study area due to the high humidity over the sampling period. High enrichment factor (EF) values (18.87-1139) were obtained for Zn, Cd, Pb and Cu reflecting the importance of anthropogenic inputs. In contrast, the EF values calculated for V, Ca, Mg, Mn, Sr and Co were low (1.05-15.81) suggesting that they were primarily of natural sources. The concentration ratios of natural sources derived elements (V, Ca, Mg, Mn and Sr) to Fe, and anthropogenic elements (Cd, Pb and Cu) to Zn are quite close in each particle size range, revealing that Fe can be a fine indicator for the prediction of ambient concentrations along with their size distributions of other elements mainly from natural processes, and Zn can be a favorable surrogate for assessment of air pollution resulting from volatile trace elements in this area. (C) 2004 Elsevier Ltd. All rights reserved.
  • 玉村 修司, 佐藤 努, 大田 由貴恵, 唐 寧, 早川 和一
    日本鉱物学会年会講演要旨集 2005 95 - 95 日本鉱物科学会 2005年 
    多環芳香族炭化水素 (PAH)は化石燃料の不完全燃焼に伴い大気中に放出される。これらの中には発癌性を有するものがあることから、PAHの地表環境での運命は大きな関心が持たれている。しかし鉱物質エアロゾルや有機エアロゾルに伴われるＰＡＨの安定性についての研究は少なく、不明な点が多い。本研究ではピレンをＰＡＨの代表物質とし、石英、αアルミナ、酸性白土（スメクタイト）およびフミン酸に伴われるピレンの安定性を相対湿度・温度コントロール下で調べた。石英、αアルミナに伴われるピレンは酸性白土やフミン酸に伴われるピレンに比べて分解速度が著しく速く、フミン酸に伴われるピレンを除き、相対湿度が増加すると分解速度は速くなる傾向が認められた。本発表では、様々な相対湿度におけるエアロゾル構成物質とＰＡＨの相互作用について考察した結果を報告する。
  • 大谷 祐介, 筒井 政則, 横山 信吾, 佐藤 努
    日本鉱物学会年会講演要旨集 2005 104 - 104 日本鉱物科学会 2005年 
    高レベル放射性廃棄物やTRU廃棄物を地層に処分する計画がある。その計画の中で緩衝材として高い物理・化学的緩衝性を持つスメクタイトを主成分としたベントナイトを使用することが考えられている。しかし坑道の補強のために大量のセメントが使われ、そのセメントが地下水と反応して劣化し、高いアルカリ性を示す地下水となり、主成分鉱物であるスメクタイトを溶解させ期待される性能が発揮されないという懸念がある。そのため、地層処分においてスメクタイトのアルカリ環境での溶解速度の決定が安全評価上重要な課題となっている。鉱物の溶解速度の一般式はLasaga(1995，1998)により示されている。スメクタイトの溶解に関する研究は数多くなされており、Ｃａｍａ et al(2000)ではｐH8．8、80℃におけるスメクタイトの溶解速度に関するΔGの影響と溶存シリカ濃度の影響の式を示している。ΔGによる影響は通常TST理論に基づいて説明されるが、Cama et al(2000)で示された式はTST理論で裏付けされるものではなく、実験から得られたデータより得られた経験式である。したがって、この経験式が、処分場で問題となっている高いｐH条件で適応可能であるのかが不明である。そこで本研究では、高アルカリ条件において溶存シリカ濃度を調整し、異なるΔG条件下で溶解実験を行うことにより、高アルカリ条件でのスメクタイトの溶解速度とΔGの関係を明らかにすることを目的とした。試料は、山形県月布産ベントナイトから精製したスメクタイト（クニピア_-_P：クニミネ工業製）を用いた。Yokoyama.et.al(2005)により試料の化学構造式は次のように示された。Na0.50K0.01Ca0.06(Al1.52Fe0.09Mg0.33)(Si 3.82Al0.18)O10(OH) 2・nH 2O本研究では、フロースルー系におけるによるスメクタイトの溶解実験を行った。実験で設定したシリカ濃度は、0.3MのNaOH にメタケイ酸ナトリウムを添加して50、100、250、500μMに設定した。また実験温度は、処分初期の地層処分場の条件を模擬するために70℃とした。固液比は1：1000とし、異なるシリカ濃度に設定した反応溶液を0.2ml/minの流量で送液し、容器内で10時間滞留するようにした。反応溶液の作成および回収は、大気中のCO2の影響によるpＨの変化を避けるため、高純度窒素雰囲気に保ったグローブボックス内で行った。溶液の回収は24時間おきに最大280時間まで行った。反応後の溶液は、モリブデンブルー法によりSi濃度を分光光度計で測定し、Al濃度についてはICP-MSにより測定した。また、反応後の固相を回収し、AFM(原子間力顕微鏡) による粒子観察から粒子の溶解による体積変化を求め、そのデータから溶解速度を見積った。実験の結果、回収した溶液は反応初期に高いSi濃度が見られたが、その後定常状態に到達していた。得られた溶存Si濃度は、初期に設定したSi濃度が50μM以上のものではそれよりも低く見積もられた。これは、シリカが高pH環境の下でポリマー化したためと考えられる。AFM観察による溶解速度の算出の結果、Siを高濃度に加えた実験で、溶解速度が遅延されていることを確認した。このことは、溶液中のΔＧが上昇するにつれ、スメクタイトの溶解速度が遅延されることを示唆している。ΔＧと溶解速度との関係は、熱力学データベースJNC990900を用いてΔＧを計算するとＣａｍａ ｅｔ ａｌ(2000)式でよく表現されていることが分かる。しかし、熱力学データベースにはSiの溶存種を見積もるのに必要な金属錯体等の形成に関するのデータの不確かさがあるため、現時点ではΔGの見積もりに不確定性が残ってしまう。今後データベースの精査とともにΔＧに関してより詳細な議論が必要であると考えられる。
  • Yokoyama, S., Kuroda, M. and Sato, T. (2005) Atomic force microscopy study of montmorillonite dissolution under highly alkaline condition. Clays and Clay Minerals, 53, 147-154.*
    2005年 [査読無し][通常論文]
  • 黄砂と燃焼粉塵による東アジア地域の環境問題
    環境情報科学 34 17 - 28 2005年 [査読無し][通常論文]
  • Wang, X.., Sato, T. and Xing, B. (2005) Sorption and displacement of pyrene in soils and sediments. Environ. Sci. Technol., 39, 8712-8718.*
    2005年 [査読無し][通常論文]
  • Suzuki, Y., Sato, T., Isobe, H., Kogure, T. and Murakami, T. (2005) Dehydration processes of the meta-autunite group minerals, meta-autunite, metasaleéite and metatorbernite. Am. Min. 90, 1308-1314.*
    2005年 [査読無し][通常論文]
  • Yokoyama, S., Watanabe, Y., Uno, H., Tamura, K., Sato, T. and Yamada, H.(2005) Adsorption and desorption behavior of ammonium ion on expandable illite, Transaction of the Material Research Society of Japan, 34, 1045-1048.*
    2005年 [査読無し][通常論文]
  • Murakami, T., Sato T., Ohnuki T. and Isobe H. (2005) Field evidence for uranium nanocrystallization and its implications for uranium transport. Chem. Geol. 221, 117-126.*
    2005年 [査読無し][通常論文]
  • Fukushi, K., and Sato, T. (2005) Using a Surface Complexation Model to Predict the Nature and Stability of Nanoparticles. Environ. Sci. Technol., 39, 1250-1256.*
    2005年 [査読無し][通常論文]
  • Pascua C., Charnock J., Polya D., Sato T., Yokoyama S., and Minato, M.(2005) Arsenic-bearing smectite from the geothermal environment, Mineralogical Magazine, 69, 899-908, 2005.*
    2005年 [査読無し][通常論文]
  • Wang, X.., Sato, T., Xing, B., Tamamura, S. and Tao, S. (2005) Source identification, size distribution and indicator screening of airborne trace metals in Kanazawa, Japan. J. Aerosol Sci. 36, 197-210.*
    2005年 [査読無し][通常論文]
  • Kida Y., Mita Y., Fukushi K. and Sato T. (2005) Mechanisms of alkaline buffering by peat and quantitative estimation of its buffering capacity. Landscape and ecological engineering, 1, 127-134.*
    2005年 [査読無し][通常論文]
  • 柴田 真仁, 須藤 俊吉, 坂本 浩幸, 佐藤 努
    日本原子力学会和文論文誌 = Transactions of the Atomic Energy Society of Japan 4 3 227 - 231 日本原子力学会 2005年 [査読無し][通常論文]
  • 横山信吾, 黒田真人, 筒井政則, 佐藤努, 鈴木啓三, 榎戸洋之
    粘土科学 44 2 45 - 52 日本粘土学会 2004年12月16日 [査読無し][通常論文]
     
    Characterization of the Kawamukai (KB) and Umenokida (UB) bentonites from the Tsukinuno bentonite mines were investigated by XRD analysis, XRF analysis, ICP-MS, petrography, SEM, AFM, and surface area determination by the N_2-BET method. XRD analyses and petrography identified quartz, feldspar, zeolite facies, calcite, and montmorillonite in the Tsukinuno bentonite. The zeolite facies in KB and UB are analcime and clinoptilolite, respectively. The Mg/(Ca+Mg) ratio of calcite based on ICP-MS in KB is higher than that in UB. These results suggest that KB has undergone a higher alteration than UB. Since no heat source such as an igneous intrusion has been reported to affect the bentonite deposits, the difference in the degree of alteration can be attributed to the effective stress applied on the deposits during folding. This is supported by the higher angle of deformation found in the KB than in UB. The layer charge distribution in montmorillonite from both bentonites indicates a bimodal distribution. Mean layer charge of Kawamukai-montmorillonite (KM) is 0.31 esu/half unit cell, which is slightly higher than Umenokida-montmorillonite (0. 29 esu/half unit cell). However, this difference in mean layer charges does not affect expandability largely. Thickness of both montmorillonite layers (i.e. KM and UM) determined with AFM is close to the height of a single hydrated montmorillonite layer. The ab dimension of UM is bigger than that of KM. This results in a large difference in the edge surface area per unit mass for UM and KM. Since the edge surface areas are more reactive, differences in physical and chemical properties such as adsorptive ability and permittivity would arise for the two bentonites.
  • Fukushi K, Sato T, Yanase N, Minato J, Yamada H
    American Mineralogist 89 11-12 1728 - 1734 2004年 [査読有り][通常論文]
  • 佐藤 努, 福士 圭介
    資源地質 53 2 193 - 200 資源地質学会 2003年12月25日 [査読無し][通常論文]
     
    Studies on natural analogues are indispensable ways to define geological disposal concepts, and to provide convincing support for the performance assessment of long-term radioactive isolation. Long-term predictions on the behavior of the natural environment are recognized to be fraught with uncertainty if based solely on information from limited and short-term observations or experiments. In this context, natural analogue studies have been extensively carried out by many researchers in the world. However, natural analogue studies have been recently scaled down and financially limited due to: (1) limited study areas that are systematically analogous to disposal sites, which is the primary prerequisite for analogue studies; (2) deficiency in defining natural analogues; and (3) lack of clarity on the utilization of data obtained in the studies and how it can contribute to performance assessment.
    Recent issues surrounding the performance assessment that should be addressed urgently in assessing the impacts on the disposal systems include: (1) retardation of anionic species such as 14CO42-, H79SeO3-, 99TcO4-; and (2) bentonite-hyper alkaline fluid (i.e. cement pore fluid) interactions. If the criteria for natural analogue studies are strictly defined, it would be very difficult to find suitable study areas. In this review, the required conditions and strategies for future natural analogue studies are discussed and summarized based on case studies of natural attenuation of arsenic in acid mine drainage and mineral paragenesis under hyper alkaline condition in Oman ophiolite.
  • 横山 信吾, 佐藤 努, 渡辺 隆
    粘土科学 43 2 64 - 70 日本粘土学会 2003年12月15日 [査読無し][通常論文]
     
    Expandability and layer charge characteristics of diagenetic illite (IMt-1) and hydrothermal sericite (HS) were investigated after alkylammonium ion exchange with potassium, and subsequently, Na Ca and Mg ion exchange. After the ion exchange, both mica clay minerals clearly exhibited expandabilitiy by intercalation of alkylammouium iion, and glycerol and water saturation in their interlayer. Differences in the expandability are mainly attributed to layer charge characteristics of expandable layers, which enabled an estimation of the distribution and amount of layer charge through X-ray diff...
  • K Fukushi, T Sato, N Yanase
    ENVIRONMENTAL SCIENCE & TECHNOLOGY 37 16 3581 - 3586 2003年08月 [査読有り][通常論文]
     
    Sorption behavior of As(V) by synthesized schwertmannite was examined under pH 3.3 as a function of As(V) concentration in the initial solution and interpreted in term of solid-solution reactions. Results showed that schwertmannite released 0.62 mmol of SO42- for every 1 mmol of H2AsO4- and 0.24 mmol of OH- that has been sorbed. As(V) replaced SO4 up to half of the total SO4 in schwertmannite. The quantitative relationship among the three chemical compositions indicated that As(V)sorbed schwertmannite would behave as a solid solution between the As(V) free schwertmannite and schwertmannite containing the maximum level of As(V). The equilibrium constant for the anion exchange in the solid-solution reaction estimated from the reacted solution chemistry depicts the As(V) content found in precipitates formed in acid mine drainage and laboratory experiments. Although schwertmannite is metastable with respect to goethite, the transformation is significantly inhibited by sorption of As(V). The solid-solution reactions also explain the stabilization of schwertmannite by sorption of As(V).
  • 福士圭介, 佐藤努
    粘土科学 42 3 148 - 153 2003年03月28日 [査読無し][通常論文]
  • 福士 圭介, 佐藤 努
    粘土科学 42 3 148 - 153 日本粘土学会 2003年03月28日 [査読無し][通常論文]
  • Fukushi K, Sasaki M, Sato T, Yanase N, Amano H, Ikeda H
    Applied Geochemistry 18 8 1267 - 1278 2003年 [査読有り][通常論文]
  • N. Yanase, H. Isobe, T. Sato, Y. Sanada, T. Matsunaga, H. Amano
    Journal of Radioanalytical and Nuclear Chemistry 252 2 233 - 239 2002年 [査読有り][通常論文]
  • 佐藤 努
    日本結晶学会誌 43 1 76 - 80 日本結晶学会 2001年02月28日 [査読無し][通常論文]
     
    At the end of 20th century, we have to summarize a progress of clay crystallography in 20th century and mention what should be needed to make a breakthrough to clay application for environmental material science in new century. Clay crystallography in 20th century illustrated that clay is a crystalline material with some stacking disorder one-dimensionally. For our 21st century with continuous development, however, we have to understand the clay surface structure and charge distribution on the surface. If we understand those, it would be available to control the performance of clay material...
  • 福士 圭介, 佐藤 努, 米田 哲朗
    粘土科学討論会発表論文抄録 45 192 - 193 日本粘土学会 2001年
  • 福士 圭介, 佐藤 努, 柳瀬 信之
    粘土科学討論会発表論文抄録 45 82 - 83 日本粘土学会 2001年
  • 佐藤 努, 横山 信吾, 岡田 朋子, 福士 圭介
    粘土科学討論会発表論文抄録 45 78 - 79 日本粘土学会 2001年
  • 福士 圭介, 佐々木 美和, 佐藤 努
    粘土科学討論会発表論文抄録 44 52 - 53 日本粘土学会 2000年
  • T Murakami, T Ohnuki, H Isobe, T Sato
    SCIENTIFIC BASIS FOR NUCLEAR WASTE MANAGEMENT XXIV 663 971 - 977 2000年 [査読有り][通常論文]
     
    Adsorption is believed to be a dominant mechanism of uranium distribution between solid and solution, and thus, to play a major role in uranium transport. Because iron oxides and hydroxides are abundant at the Earth's surface and are great adsorbents of uranium, we have examined natural rocks that contain iron minerals along with uranium, and also carried out Fe-U coprecipitation and aging experiments to find how uranium is distributed between Fe minerals. Transmission and scanning electron microscopy reveals that microcrystals (10-50 nm) of metatorbernite (Cu(UO(2))(2)(PO(4))(2).8H(2)O) are scattered within nodules consisting of fine-grained (2-50 nm) goethite and hematite, where the ground water is undersaturated with respect to metatorbernite, for the natural rocks from the Koongarra ore deposit, Australia. The microscopy also reveals that microcrystals (a few nm) of dehydrated schoepite ((UO(2))O(0.25)(OH)(1.5)) are formed among fine-grained hematite after aging coprecipitated Fe-U in the laboratory, and the solution is undersaturated with respect to schoepite. The beam size of microscopes is found to be important for the chemical analysis of such microcrystals. We detect a strong signal of uranium for a beam size < 40 nm; whereas a weak uranium signal is obtained for a beam size > 150 nm. Our results indicate that such a weak uranium signal should not be taken as a result of homogeneously distributed uranium over goethite and hematite surfaces by, for instance, adsorption. The micrcrystallization observed in both the field and laboratory suggests that fine grained uranyl minerals play a major role in uranium transport and migration.
  • T Nagano, T Sato, IS Williams, M Zaw, TE Payne, PL Airey, N Yanase, H Isobe, T Ohnuki
    GEOCHEMICAL JOURNAL 34 5 349 - 358 2000年 [査読無し][通常論文]
     
    SHRIMP analyses have been conducted for rock samples from the Koongarra secondary ore deposit in Northern Australia to obtain activity ratios of U-234/U-238 and isotopic ratios of Pb-207/Pb-206 and Pb-204/Pb-206, and to understand their migration behavior within the secondary ore deposit. Main Larger minerals for the analyses were iron minerals and kaolinite, which are the main weathering products in this area. The activity ratios of U-234/U-238 were based on SHRIMP counts at the mass of uranium metal. The U-234/U-238 activity ratios based on counts of uranium oxides were not satisfactory, because the count rates of (UO)-U-234-O-16 were affected by interference from the (UC)-U-238-C-12 fragment. The activity ratios of U-234/U-238 were approximately unity for crystalline iron minerals, whereas the amorphous iron minerals (precursors of the crystalline iron minerals) had also values above unity. The mean residence time of uranium within the iron nodules was estimated to be up to approximately 2-3 million years. Results of lead isotopes, represented by a diagram of Pb-207/Pb-206 VS. Pb-204/Pb-206, indicated that the present three samples contained radiogenic lead, common lead and mixture of both components. In addition, the recent radiogenic lead component within the primary ore is dominant in the area closer to the primary ore. The radiogenic lead isotope compositions of samples at greater distances from the primary ore have been affected only by the earlier mobilization event of radiogenic lead. All these results indicate that some geologic event causing migration of the radiogenic lead had occurred before formation of the secondary ore deposit due to the weathering. After the weathering commenced at least 2-3 million years ago, uranium and lead have migrated from the primary ore. While the uranium has dispersed throughout the secondary ore deposit, the lead reached only the area closer to the primary ore probably due to its immobility compared to the uranium.
  • Takashi Murakami, Tsutomu Sato, Atsuyuki Inoue
    American Mineralogist 84 7-8 1080 - 1087 1999年 [査読有り][通常論文]
     
    To elucidate the process and mechanism of the prograde conversion of saponite to chlorite through corrensite, the microstructures of a series of chlorite-smectite (C-S) mixed-layer samples from Kamikita, northern Japan were examined by high-resolution transmission electron microscopy using both lattice and structure imaging. Corrensite grows epitaxially as domains of 5-20 nm thick mainly within homogeneous saponite domains, without forming randomly interstratified C-S. Then, chlorite domains grow outside homogeneous corrensite domains without forming randomly interstratified C-S or chlorite-corrensite (C-Co), and finally are predominant. An atomic resolution image suggests that corrensite essentially consists of the 1 M stacking of alternating chloritic and smectitic layers. The structure and occurrence suggest corrensite is mineralogically a unique species. Comparison of the stacking vectors of corrensite along [001] to those of chlorite reveals that the stacking sequence is not inherited during the process from corrensite to chlorite. We rarely observed layer terminations of the hydroxide sheets both in corrensite and chlorite domains, and the layer terminations that do exist can be explained as defects rather than the formation of corrensite or chlorite. Our data strongly suggest that the saponite-to-chlorite conversion series progresses stepwise from saponite to corrensite and from corrensite to chlorite, and that the dominant reaction mechanisms are dissolution and precipitation.
  • T Sato, N Yanase, IS Williams, W Compston, M Zaw, TE Payne, PL Airey
    RADIOCHIMICA ACTA 82 335 - 340 1998年 [査読有り][通常論文]
     
    The SHRIMP II was used to measure the (234)U/(238)U isotope ratios in weathered rock from the Koongarra uranium (U) deposit in Northern Australia. The results were compared with data obtained using sequential extraction (SE) procedures. The key attribute of the SHRIMP measurement is that sensitive isotopic data can be obtained without dissolution of the sample, and associated loss of textural relationships. The SHRIMP provides spot-by-spot isotopic ratios in individual mineral phases, and has not been previously applied to measurements of 234U/238U ratios. The SHRIMP measurements of (234)U/(238)U activity ratios in the accumulated iron (Fe)-materials were closer to unity than in the chemically extracted amorphous Fe-oxide fraction, the primitive phase of all Fe-minerals. This indicates an approach to secular equilibrium subsequent to the deposition of U with the amorphous precursor phases. The activity ratios of (234)U/(238)U in kaolinite were significantly lower than the ratios obtained for residual mineral phases in the SE study, although being higher than unity. This suggests that the extremely high (234)U/(238)U ratio of the residual phase in the SE study was mainly derived from other minerals, presumably the abundant quartz rather than the kaolinite. Activity ratios exceeding unity were found in all kaolinites studied, regardless of their proximity to U-rich phases and grain boundaries. Individually, the SE procedure and SHRIMP analysis are useful techniques for measuring isotopes within mineral phases. However, in contrast to the SHRIMP the SE procedure does not provide spatial or textural information, and quantifies isotopes in individual extractable fractions. On the other hand, the SHRIMP is not suitable for phases with very small grain size or low U content. By the parallel use of SE procedures and the SHRIMP samples can be analyzed both quantitatively and with high spatial resolution.
  • Y Suzuki, T Murakami, T Kogure, H Isobe, T Sato
    SCIENTIFIC BASIS FOR NUCLEAR WASTE MANAGEMENT XXI 506 839 - 846 1998年 [査読有り][通常論文]
     
    The crystal chemistry and microstructures of saleeite (Mg(UO2PO4)(2) . 10H(2)O) and metatorbernite (Cu(UO2PO4)(2) . 8H(2)O), from Koongarra, Australia and Shinkolobwe, Congo, were examined by X-ray diffraction analysis, infrared spectroscopy (IR), scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis, transmission electron microscopy (TEM) and analytical electron microscopy. The uranyl phosphates consist of uranyl phosphate layers with cations and waters in the interlayers. The IR spectra of saleeite and metatorbernite show the presence of hydroxyls in the interlayers in addition to water molecules. The d(002) spacings of the hydrated phases of saleeite and metatorbernite up to 300 degrees C reveal that the uranyl phosphate layers themselves are quite stable in the temperature range although the interlayer water molecules are lost easily. The presence of a mixed phase of saleeite and metatorbernite is confirmed in the micrometer and nanometer scales. However, SEM and TEM examination suggest saleeite and metatorbernite generally grow separately, and rarely form solid solution or interstratification. The results imply that U is retained in uranyl phosphate minerals even when the temperature at around repositories increases, and that saleeite and metatorbernite precipitate independently from solution according to their solubilities even when Mg2+ and Cu2+ coexist in solution.
  • T Sato, T Murakami, N Yanase, H Isobe, TE Payne, PL Airey
    ENVIRONMENTAL SCIENCE & TECHNOLOGY 31 10 2854 - 2858 1997年10月 [査読有り][通常論文]
     
    The scavenging of uranium from groundwater downgradient of the uranium ore deposit at Koongarra, Australia, has been investigated to provide information about the longterm transport of radionuclides. Rock samples collected from diamond-drill co res we re examined mainly using scanning and transmission electron microscopy. Here we focus on the U associated with iron oxides and report on (i) the extent to which U has accumulated in the various types of iron oxides (fissure fillings, clay coatings, and nodules) and (ii) the chemical form of U associated with iron-nodules. The iron nodules have a remarkably large capacity for uranium uptake. The uranium enrichment in the nodules reaches approximately 8 wt %, and their uranium contents are greater than those in the other iron forms, such as fissure fillings and clay coatings. The ability of the iron nodules to enrich uranium (to levels 10(6) times higher than the groundwater) is greater than those of any other natural materials in the system. Although the initial step in uranium uptake appears to he adsorption,the uranium in the nodules has been fixed by precipitation of copper uranyl phosphate microcrystals. This precipitation process leads to the long-term retardation of uranium in ?he system. This result strongly suggests that an understanding of postadsorption processes is necessary for predicting radionuclide retardation over long time scales.
  • T Murakami, T Ohnuki, H Isobe, T Sato
    AMERICAN MINERALOGIST 82 9-10 888 - 899 1997年09月 [査読有り][通常論文]
     
    Mineralogical and geochemical mechanisms of U fixation under oxidizing conditions in the vicinity of the secondary U ore deposit at Koongarra, Australia, were examined using transmission and scanning electron microscopy and thermodynamic calculations. The formation of saleeite, Mg(UO2)(2)(PO4)(2) . 10H(2)O, is the predominant mechanism for U fixation upstream from the deposit, where saleeite replaces sklodowskite and granular apatite. Within the deposit and further downstream, U is fixed in microcrystals (10-50 nm) of saleeite and (meta)torbernite scattered within veins of fine-grained (2-50 nm) Fe3+ minerals (primarily goethite and hematite). Thermodynamic calculations indicate the groundwater is undersaturated with respect to saleeite and metatorbernite and that these minerals should precipitate at higher U or P concentrations than observed. This suggests that the upstream saleeite precipitated at the reaction interfaces of dissolving sklodowskite and apatite under local saturation conditions. Observed textural relationships of saleeite and (meta)torbernite microcrystals with the Fe minerals, combined with thermodynamic calculations, suggest surface precipitation as the formation mechanism for saleeite and (meta)torbernite microcrystals within, and downstream from, the secondary ore deposit. Phosphorous released during the aging of ferrihydrite and U adsorbed onto Fe minerals are probably the sources of the major components of the microcrystals. Downstream, the microcrystals exist where groundwater U concentrations ate as low as 10-30 mu g/L. Once released from the ore deposit, U is fixed in uranyl phosphates even where measured groundwater is undersaturated with respect to uranyl phosphates. The surface precipitation is an important example of long-term post-adsorption U fixation in a natural system. The fully crystalline and radiation-damaged microstructures of saleeite indicate uranyl phosphates have formed continuously (or intermittently) for the last few million years.
  • 佐藤 努
    鉱物学雜誌 = Journal of the Mineralogical Society of Japan 25 3 99 - 110 日本鉱物学会 1996年07月01日 [査読無し][通常論文]
  • T Murakami, H Isobe, T Sato, T Ohnuki
    CLAYS AND CLAY MINERALS 44 2 244 - 256 1996年04月 [査読有り][通常論文]
     
    The weathering of chlorite, one of the major minerals of the host rock in the uranium ore deposit at Koongarra, Australia, was examined by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), electron microprobe: analysis, and transmission electron microscopy (TEM). The conversion sequence of chlorite weathering is: (1) chlorite; (2) chlorite/vermiculite intergrade (showing XRD responses to various treatments intermediate between those of chlorite and vermiculite); (3) interstratified chlorite and vermiculite; (4) vermiculite; and (5) kaolinite. This sequence may be more simply expressed as chlorite --> vermiculite --> kaolinite. The weathering finally changed chlorite into sub-micrometer to micrometer sized Fe minerals and kaolinite. The transformation of chlorite to vermiculite is chemically characterized by an Fe and Mg loss with a slight decrease in the Al/Si ratio. Mg continues to be released throughout the weathering. Fe minerals formed through chlorite weathering are located between chlorite and vermiculite domains (a few mu m in size) at first, and then accumulated between grain boundaries, occasionally forming veins. The distribution of Fe minerals is suggestive of preferential pathways of water movement. The time-dependent nature of mineral alteration demonstrated in the present study must be taken into account for the quantitative estimation of radionuclide migration.
  • Tsutomu Sato, Takashi Murakami, Takashi Watanabe
    Clays and Clay Minerals 44 4 460 - 469 1996年 [査読有り][通常論文]
     
    The changes in amount and location of layer charge during diagenetic alteration have been investigated for smectites and smectite layers of illite/smectite interstratified minerals (I/S) by X-ray powder diffraction analysis with various expansion behavior tests: 1) ethylene glycol (EG) solvation (XRD) 2) K-saturation and EG solvation 3) Li-saturation, heating at 250 °C and glycerol or EG solvation (Greene-Kelly test) and 4) alkylammonium saturation. In the course of low-temperature diagenesis but before the onset of illitization, mean layer charge of smectites continuously increases from approximately 0.56 to 0.73 per O20(OH)4 with increasing depth, and tetrahedral charge also increases continuously from approximately 0.21 to 0.38 per O20(OH)4 (beidellitization). The continuous increase in tetrahedral charge without change in peak intensity and shape suggests that the solid-state Al for Si substitution mechanism appears to predominate within beidellitization. After illitization, the content of the beidellitic layers continuously decreases, while the mean layer charge of expandable layers and the content of illite layers in I/S increase. This suggests that the conversion of a beidellitic layer to an illitic layer preferably occurs during early illitization. Thus, before illitization, beidellite-like layers are formed from precursor smectite, and during the early stage of illitization, the high charged beidellitic layers are probably consumed to form illite layers.
  • T Murakami, H Isobe, T Ohnuki, T Sato, N Yanase, J Kiyoshige
    SCIENTIFIC BASIS FOR NUCLEAR WASTE MANAGEMENT XIX 412 809 - 816 1996年 [査読有り][通常論文]
  • T MURAKAMI, K TSUZUKI, T SATO, H ISOBE, T OHNUKI
    SCIENTIFIC BASIS FOR NUCLEAR WASTE MANAGEMENT XVIII, PTS 1 AND 2 353 1219 - 1226 1995年 [査読有り][通常論文]
  • T OHNUKI, T MURAKAMI, H ISOBE, T SATO, N YANASE
    SCIENTIFIC BASIS FOR NUCLEAR WASTE MANAGEMENT XVIII, PTS 1 AND 2 353 1227 - 1234 1995年 [査読有り][通常論文]
  • T SATO, T MURAKAMI, H ISOBE, T OHNUKI
    SCIENTIFIC BASIS FOR NUCLEAR WASTE MANAGEMENT XVIII, PTS 1 AND 2 353 239 - 246 1995年 [査読有り][通常論文]
  • 佐藤努
    日本原子力学会誌 36 5 405 - 412 日本原子力学会 1994年05月 [査読無し][通常論文]
  • T OHNUKI, T MURAKAMI, T SATO, H ISOBE
    RADIOCHIMICA ACTA 66-7 323 - 326 1994年 [査読有り][通常論文]
     
    The redistribution of strontium and cesium during the alteration of smectite to illite has been studied under hydrothermal conditions at 200 degrees C using solutions of 1 x 10(-4) M Sr and Cs. Two different sorption conditions were applied for the hydrothermal experiments. One was the condition in which strontium and cesium were sorbed by smectite before the hydrothermal experiments (dynamic condition). The other was the condition in which strontium and cesium were sorbed by the alteration products, illite/smectite (I/S) interstratified minerals after the hydrothermal experiments (static condition). The sorption characteristics of strontium and cesium by smectite, I/S interstratified minerals were examined by a sequential extraction method. Most of the strontium was desorbed from smectite and the I/S interstratified minerals with a 1 M KCl solution under both the dynamic and static conditions. Less than 1% of cesium was desorbed from the I/S interstratified minerals with any solution of a 1 M KCl, a 1 M HCl and a 6 M HCl under the dynamic condition, while most of cesium was desorbed with either solution of a 1 M KCl and 1 M HCl from smectite and from the I/S interstratified minerals under the static condition. These suggest that cesium sorbed by smectite changes its sorption characteristic during the alteration process, but strontium does not. Possible sites for more strongly bounded cesium to the I/S interstratified minerals may be at the 'ditrigonal cavity' of adjacent tetrahedral layers.
  • T MURAKAMI, T OHNUKI, H ISOBE, T SATO, N YANASE, H KIMURA
    SCIENTIFIC BASIS FOR NUCLEAR WASTE MANAGEMENT XVII 333 645 - 652 1994年 [査読有り][通常論文]
  • T Ohnuki, T Murakami, T Sato, H Isobe
    CHEMISTRY AND MIGRATION BEHAVIOUR OF ACTINIDES AND FISSION PRODUCTS IN THE GEOSPHERE 327 - 330 1994年 [査読有り][通常論文]
  • 村上 隆, 佐藤 努, 井上 厚行
    粘土科学 33 3 35 - 36 日本粘土学会 1993年12月30日 [査読無し][通常論文]
  • 佐藤 努, 村上 隆
    粘土科学討論会発表論文抄録 37 33 - 34 日本粘土学会 1993年
  • 大貫敏彦, 村上隆, 佐藤努, 磯部博志
    日本原子力学会誌 34 12 1139 - 1142 1992年12月 [査読無し][通常論文]
  • Tsutomu Sato, Takashi Watanabe, Ryohei Otsuka
    Clays and Clay Minerals 40 1 103 - 113 1992年 [査読有り][通常論文]
     
    Expansion properties of ten homoionic smectites that differed in amount and location of layer charge were examined by X-ray powder diffraction analysis at various relative humidities, or after glycerol or ethylene glycol solvations. Except for K-samples with glycerol solvation, and Na- and Ca-samples with ethylene glycol, differences in the basal spacings are observed in samples having similar layer charge. These results show that the basal spacings are larger when the layer charge is located in octahedral sites than when it is in tetrahedral sites. This suggests that expansion is due to the combined effects of the charge location and amount. The effects of layer charge magnitude and location on expansion were represented by an energy change (expansion energy: ΔEr) during the hydration and solvation processes. Plots of basal spacings versus ΔEr show a reasonable relationship the spacings generally decrease stepwise as the value of ΔEr increases. The basal spacings of K-samples with glycerol solvation, Na-saturated and K-saturated samples at 100% RH are apt to contract stepwise with increasing value of ΔEr. For these samples, the figures showing the relationship between each expanded phase and the charge characteristics are obtained from the isoquants of ΔEr, given the boundary of the expanded phases. A behavior test using these figures may be combined with the Greene-Kelly test to estimate the amount and the location of the layer charge of common smectites. © 1992, The Clay Minerals Society.
  • 佐藤 努, 安藤 善之, 渡辺 隆, 大塚 良平
    粘土科学 31 3 143 - 149 日本粘土学会 1991年11月20日 [査読無し][通常論文]
     
    A relative humidity (RH) control cell for measurement of infrared absorption spectra (ReCCIR) was developed to investigate states and amounts of water in some clay minerals. The reproducible infrared spectrum can be obtained by the ReCCIR under the condition of 0-100% RH at 25℃. Using the ReCCIR, the following investigations are performed : the observation of hysteresis in hydration-dehydration process of smectite and the rehydration properties of the dehydrated smectite, and the quantitative estimation of halloysite ratio in the mixture of kaolinite and halloysite.
  • 安藤 善之, 佐藤 努, 渡辺 隆, 大場 孝信
    粘土科学 31 3 150 - 160 日本粘土学会 1991年11月20日 [査読無し][通常論文]
     
    The Plio-Pleistocene Seto Group is distributed in the Onada district, Tajimi City; Gifu Prefecture. The Tokiguchi Formation that is the lower part of the Seto Group is rich in clay. The constituent minerals of the sediment are quartz, kaolin mineral and smectite. Some samples contain small amount of mica mineral and lepidochrocite. Moreover, the mineralogical properties of the clay were examined by means of X-ray diffraction, electron microscopy and infrared spectroscopy In the present investigation, the kaolin mineral in the Tokiguchi Formation is mainly composed of b-axis disordered kaoli...
  • 佐藤 努, 磯部 博志, 渡辺 隆
    粘土科学 31 1 32 - 37 日本粘土学会 1991年05月20日 [査読無し][通常論文]
     
    Diagenetic illite/smectite interstrafitied minerals (I/S) from Neogene shales and sandstones in the regions of the Yachi River and Nakanomata River, Niigata Pref. (Japan) are examined by X-ray diffraction (XRD). The decrease of smectite percentage in I/S takes place continuously from 100% to 30%. The I/S from sandstone laminae tend to be of higher expandability than from adjacent shale laminae belonging to the same horizon. Some of XRD patterns indicate that intermediate stage exists at the conversion process from g=0 to g=1. It is due to the mixture or the segregated structure with random ...
  • 佐藤 努, 大塚 良平, 渡辺 隆
    粘土科学討論会発表論文抄録 35 104 - 105 日本粘土学会 1991年
  • 村上 隆, 佐藤 努, 磯部 博志
    粘土科学討論会発表論文抄録 35 102 - 103 日本粘土学会 1991年
  • 佐藤 努, 村上 隆, 磯部 博志, 渡辺 隆
    粘土科学討論会発表論文抄録 35 106 - 107 日本粘土学会 1991年
  • 佐藤努, 藤井美香, 渡辺隆, 大塚良平
    鉱物学雑誌 19 17 - 22 日本鉱物学会 1990年03月 [査読無し][通常論文]
  • 佐藤努, 渡辺隆
    岩鉱 84 8 259 - 269 日本岩石鉱物鉱床学会 1989年08月 [査読無し][通常論文]
  • 渡辺 隆, 佐藤 努
    粘土科学討論会発表論文抄録 32 84 - 84 日本粘土学会 1988年
  • 佐藤 努, 渡辺 隆
    粘土科学討論会発表論文抄録 31 69 - 69 日本粘土学会 1987年
  • 渡辺 隆, 佐藤 努
    粘土科学討論会発表論文抄録 31 70 - 70 日本粘土学会 1987年
  • 渡辺 隆, 佐藤 努
    粘土科学討論会発表論文抄録 30 8 - 8 日本粘土学会 1986年

MISC

所属学協会

  • 国際鉱物学連合   資源・素材学会   日本原子力学会   地球化学学会（Geochemical Society）   粘土鉱物学会（Clay Minerals Society）   日本鉱物科学学会   日本粘土学会   Atomic Energy Society Japan   Geochemical Society   Clay Minerals Society   MIneralogical Society of Japan   Japan (1992-)Member of Mining and Materials Processing Institute of Japan (2005-)   Japan (1989-)Geochemical Society (1992-)Atomic Energy Society   Japan (1989-)Clay Minerals Society (1989-)Mineralogical Society   Clay Mineralogical Society   

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 佐藤 努, 大竹 翼
     
    本研究では、合成実験とその生成物の精緻なキャラクタリゼーション、熱力学的な検討、様々な天然環境での探索と産出の確認、地質学的時間スケールでの経時変化の観察などにより、マグネシウムシリケート水和物(M-S-H）の正体（組成や構造等）が明らかとなり、生成条件に対する理解が深まり、その生成を予測可能な地球化学的反応モデルやデータベースも構築・検証することできた。したがって、これからはM-S-Hの生成が予想される様々な工学シーンで、検証されたモデルやデータベースを使ってM-S-H生成の可否や生成量の予測が可能となり、M-S-Hの生成を加速・抑制するための方策も検討可能となった。
  • 英知を結集した原子力科学技術・人材育成推進事業 汚染水処理で発生する合成ゼオライトと チタン酸塩のセメント固化体の核種封じ込め性能の理解とモデル化 およびその処分システムの提案
    文部科学省：国家課題対応型研究開発推進事業 英知を結集した原子力科学技術・人材育成推進事業
    研究期間 : 2016年11月 -2019年03月 
    代表者 : 佐藤 努
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2015年04月 -2018年03月 
    代表者 : 佐藤 努, 廣吉 直樹, 小暮 敏博
     
    産地の異なる汚染土壌の約4万粒子を詳細に調べたところ、放射性セシウムを濃集している粒子の割合はわずか0.3%であった。また、これら濃集粒子は、風化雲母の凝集体、有機物と風化雲母の複合体、風化雲母片であり、様々な構成鉱物の中で風化風雲母片が最もセシウムを濃集できることは、吸着実験結果とも整合的であった。観察した土壌からはガラス球状物質は見出されなかったので、セシウムの主たるホストは風化雲母と結論された。この風化黒雲母は磁気分離可能なことから、ポールミルや超音波等により風化黒雲母片を解砕し、磁選によって効率的に回収することで、合理的な減容化が可能となることが判明した。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2013年04月 -2018年03月 
    代表者 : 石黒 宗秀, 柏木 淳一, 佐藤 努, 小林 幹佳, 北川 巌, 鈴木 克拓
     
    養分の有効利用を図り、土壌・水・大気汚染対策を確立するために、吸着実験・分散凝集実験・水田圃場調査を行うと共に、吸着理論・分散凝集理論・溶質移動理論を適用した．リン酸のカオリナイト粘土への吸着機構と熱帯土壌フェラルソルの分散凝集特性、ストロンチウムの種々粘土への吸着特性と移動の抑制効果、アニオン性界面活性剤の多腐植質土壌への吸着機構を明らかにした．また、津波被害を受けた農地の除塩対策の基本的方策を提案し、二酸化炭素の水田への貯留効果を明らかにした．
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2012年05月 -2016年03月 
    代表者 : 池田 泰久, 三村 均, 佐藤 修彰, 新堀 雄一, 小崎 完, 佐藤 努, 佐々木 隆之, 桐島 陽, 出光 一哉, 稲垣 八穂広, 鈴木 達也, 竹下 健二
     
    福島原発事故で発生した汚染物の合理的な処理・処分システム構築に向け、従来とは異なる固体・液体汚染物の性状研究、固体・液体汚染物の処理研究、発生廃棄物の処分研究の3分野に分け、基盤データの取得を行ってきた。 その結果、燃料デブリの性状、核種の溶出挙動、汚染物の除染法、汚染水の処理法、高塩濃度環境下での核種の移行挙動等、燃料デブリをはじめとした従来知見の少ない海水を含む水溶液に接する条件下で発生した放射性廃棄物の処理・処分技術の開発に資する多くのデータを取得し、福島原発事故廃棄物の処理・処分方策に貢献しうるとともに、放射性廃棄物の処理・処分分野の進展に寄与しうる成果を出している。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2011年04月 -2015年03月 
    代表者 : 柏谷 健二, 長谷部 徳子, 青木 賢人, 福士 圭介, 遠藤 徳孝, 山本 正儀, 長尾 誠也, 斎藤 享治, 鴈澤 好博, 佐藤 努, 飯田 肇, 梁 東潤, 南 穎, 李 春景, 田中 幸哉, DONDOV Tumurhoo, 林 俊全
     
    １）中国東北部の湖沼－流域系の調査とコア試料分析から、後期完新世以降（約2800年前）の乾燥・寒冷化と約1000年前以降の人為的環境変動が明らかにされた。2) 台灣中央部の日月潭の湖沼堆積物の分析結果とその流域の調査から、後期完新世以降（約2500年前）の乾燥・寒冷化と約100年前のダム化による環境変動が明らかにされた。3) 北海道渡島大沼の湖沼－流域系の調査とコア試料分析から、1640年の大噴火以降の環境変動、そして戦後の人為的環境変動が明らかにできた。4) 金沢での池沼－流域系では観測資料およびセディメントトラップ試料の分析により、自然と人為による環境変動が識別できることが明らかになった。
  • 文部科学省：科学研究費補助金(基盤研究(B))
    研究期間 : 2012年 -2012年 
    代表者 : 佐藤 努
     
    本研究では、福島第一原子力発電所事故で環境中に放出されたセシウムを固定している粒子を明らかにし、それを基に、土壌の減容化を可能とする分級方法や合理的で安全なセメント固化法について提案することを目的とした。その結果、放射性セシウムを多く吸着している粒子は、複数の鉱物の凝集態、有機物と鉱物の複合体、風化雲母片に大別され、これらは多孔質天然材料である珪藻土、あるいは通常の湿式分級法により分級可能であることが明らかとなった。さらに、固定化されていないセシウムはゼオライトで吸着除去した後に処分することが予想されるが、通常のスラグセメントで浸出性の低い安全な固化体となることが明らかとなった。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2009年 -2011年 
    代表者 : 佐藤 努, YOGARAJHA Elakneswaran
     
    本研究により、主に以下の3つについて大きな成果が得られた。 セメントとベントナイトを構成する鉱物表面の性能の決定 ベントナイトの表面性能については数多くの研究報告があるが、セメントの主たる水和鉱物であるカルシウムケイ酸水和物(CSH)の表面特性に関してはあまり詳しく理解されていなかった。本研究では、実験とモデルによる計算結果の照合プロセスにより、CSHの表面特性を明らがにした。CSHの表面特性を明らかにできたことにより、放射性廃棄物処分場における長期性能評価に資する輸送・反応モデルを提示することが可能となった。 セメント鉱物表面と核種の相互作用 セメント鉱物による核種の移行遅延は表面吸着や表面沈殿によるが、それらをモデル計算に組み込むためのパラメータ取得は十分ではなかった。そこで、安全評価上重要な核種と考えられている^<129>I^-を対象として、コールドの拡散実験とモデル計算の結果の比較を行った。その結果、ヨウ素については静電的な吸着は期待できず、比較的容易に移行することが明らかとなった。 様々な反応を統合した熱力学的モデルの開発 上述のように、本研究では地球化学モデリングソフトのPHREEQCを使用して、表面錯体モデル、相平衡モデル、多種イオン拡散モデルを組み合わせ、硬化体中を浸透する塩化物イオンの挙動を評価した。その結果、ここで開発したモデルは、本実験結果や既報の実験結果における塩化物イオンの移動プロファイルおよび様々なセメントにおけるプロファイルの相違を説明できるものであることが明らかとなった。
  • 文部科学省：科学研究費補助金(基盤研究(B))
    研究期間 : 2009年 -2011年 
    代表者 : 佐藤 努, 道林 克禎, 長沼 毅, 鈴木 雅一, 上田 晃
     
    22年度は12月から1月にかけて、研究代表者、研究分担者の一部、連携研究者の一部とそれぞれの研究室に所属する大学院生が参加する現地調査を行った。現地調査の目的は、(1)高アルカリ泉を作り出す地質学的条件とその地球科学・地球工学的インパクトの解明、(2)高アルカリ環境における地球化学的諸現象(沈澱、吸着、表面錯体、固液分配等)の解明、(3)高アルカリ環境に適応した微生物群集や動物種のスクリーニングとその適応機構の解明、(4)自然が作り出したコンクリートの長期挙動とその生成に学ぶ二酸化炭素貯留法の解明である。調査では、アルカリ泉周辺の岩石、水、沈殿物(微生物を含む)、魚・カエルなどの動物採集を行い、より詳細な分析が必要な試料については適切な処理を施した後に日本に持ち帰り、グループ毎に専門的な見地から分析を行った。その結果、(1)高アルカリ泉を作り出す地殻一マントル境界に発達したマントル延性剪断帯の構造が明らかとなった、(2)高アルカリ環境における炭酸塩鉱物の生成とその速度式を導くことができた、(3)高アルカリ泉から新規微生物遺伝子や16株の炭酸塩形成候補菌の分離・同定に成功した、(4)高アルカリ泉の周囲に3種の淡水魚と1種の無尾両生類の棲息を確認し、中でも淡水魚のG.barreimiaeは80%アルカリ温泉水への適応能を持つことが明らかになった。また、9月に広島大学で、具体的な研...
  • 文部科学省：科学研究費補助金(萌芽研究, 挑戦的萌芽研究)
    研究期間 : 2007年 -2009年 
    代表者 : 佐藤 努, 福嶋 正巳, 米田 哲朗
     
    21年度は、昨年度より行ってきた構造や組成の異なる単一鉱物のペプチド生成反応に対する触媒作用の比較・検討を継続するとともに、それらの共生効果についての検討を行った。今回検討した鉱物は、Ca-、Na-、H型モンモリロナイト、γ-アルミナ、ヘクトライト、バイデライト、石英、ペリクレイス、カルサイト、ドロマイト、カオリナイト、クリソタイル、ハイドロタルサイトである。今回の実験で生成されたペプチドは、2量体の環状無水物(DKP)と2～6量体の直鎖状ペプチドであった。鉱物を付加しないコントロールと比べると、鉱物を用いた全ての実験で鉱物によるアミノ酸重合触媒作用が認められた。ただし、ペプチドの生成量は使用した鉱物によって顕著な違いが認められ、高い触媒能を示したのはカルサイトやドロマイト等の炭酸塩鉱物であった。また、ほとんどの鉱物は相対湿度50%にて最も高い触媒効果を示し、相対湿度を制御して鉱物表面でのDKP生成を抑制し、より長い直鎖のポリペプチドの生成を可能にしているものと推定する。また、2つの鉱物を混合した系でのペプチド生成反応に対する触媒作用を比較検討したところ、モンモリロナイトとカルサイト、ハイドロタルサイトとカルサイトを混合した系で、単一鉱物を用いた系より顕著に高い触媒作用を示すことが明らかとなった。これはカルサイト表面が負に帯電しているため、アミノ基がカルサイト表面において脱プ...
  • 文部科学省：科学研究費補助金(基盤研究(A))
    研究期間 : 2007年 -2009年 
    代表者 : 金子 勝比古, 高橋 弘, 五十嵐 敏文, 佐藤 努, 村田 澄彦, 川崎 了, 伊藤 真由美
     
    マイクロ・リストラクチャリングの要素技術とその工学的応用に関する一連の研究を実施した。特に,微視構造の人為的改変による物性改良法として,環境制御により微視亀裂進展を抑制させて強度を改善する方法,微生物代謝を利用して炭酸カルシウムやシリカを析出させて間隙を充填する方法,還元環境操作により地下水中から炭酸カルシウム等の鉱物を析出させて亀裂を閉塞させる方法など,工学的目的に応じた複数の手法を開発した。
  • 文部科学省：科学研究費補助金(基盤研究(B))
    研究期間 : 2007年 -2009年 
    代表者 : 川西 琢也, 佐藤 努, 齋藤 雅彦, 福士 圭介, 佐藤 努, 齋藤 雅彦, 福士 圭介
     
    ヒ素不溶化資材であるシュベルトマナイトについて,共存物質,pHのなどの影響を実験をもとに表面錯体モデルで整理した。汚染土壌不溶化の空間スケールでは,溶液中拡散が初期のべき乗則ステージにあることを明らかにし,均質体ではべき乗の指数がマイナス0.5であるが,水分分布の不均質な系ではマイナス0.5～マイナス1.0の値をとり得ることを明らかにした。バリア工法の検証とともに、土壌重金属汚染不溶化技術の「確実な」設計支援をするサブモデル群を構築することに成功した。
  • 文部科学省：科学研究費補助金(基盤研究(A))
    研究期間 : 2006年 -2008年 
    代表者 : 柏谷 健二, 長谷部 徳子, 佐藤 務, 青木 賢人, 山本 政儀, 河合 崇欣, 箕浦 幸治, 酒井 英男, 高原 光, 長谷部 徳子, 福士 圭介, 佐藤 努, 青木 賢人
     
    フグスグル湖湖底堆積物の採取と分析、バイカル湖湖底堆積物の分析そしてその周辺の環境解析から、ユーラシア東部内陸部における環境変動については以下のことが示唆された。1)最終間氷期(MIS5e)から亜氷期(MIS5d)への移行は急激であり、MIS5dは氷期に相当するような寒冷期であった、2)MIS11は亜氷期を伴う超間氷期であった、3)最終氷期においては内陸部でも5千~1万年スケールのBond Cycleに対応する環境変動があった。
  • 文部科学省：科学研究費補助金(基盤研究(B))
    研究期間 : 2005年 -2007年 
    代表者 : 佐藤 努, 早川 和一, 川西 琢也, 柏谷 健二
     
    多環芳香族炭化水素(PAH)が国境を超えて長距離運搬されることについて世界の各地で報告がなされてきたが、近年の東アジア諸都市の著しい経済発展にもかかわらず、日本海を越える長距離運搬は明らかにされてこなかった。本研究では金沢において2003年の春季からおよそ1年間エアロゾルをサンプリングし、黄砂粒子に伴われるPAHの長距離運搬に関して検討した。また、黄砂構成鉱物粒子表面に吸着したPAHの安定性について実験的に検討した。観測期間中に黄砂飛来が確認されたサンプリング期間は3期間で、それぞれ黄砂現象確認時期1(3月11日〜19日、2004)、2(3月28日〜4月9日、2004)および3(4月9日〜4月25日)であった。黄砂粒子の粒径は通常時に比べ比較的粗粒(2.2-11μm)であることが確認された。PAHは粗粒(2.2-11μm)のエアロゾルと細粒(<1.1μm)のエアロゾルからそれぞれ抽出・定量された。その結果、黄砂現象確認時期3の黄砂には、高濃度のBenzo [a] pyrene (BaP)やBenzo [g, h, i] perylen (BghiP)などの揮発性の低いPAHが含まれていた。これらの揮発性の低いPAHはガス状として存在する濃度が小さく、東アジア大陸内部の元々PAHに汚染された土壌からもたらされたものと推定された。後方流跡線解析の結果、黄砂現象確認時期3の黄砂は工...
  • 文部科学省：科学研究費補助金(基盤研究(A))
    研究期間 : 2004年 -2006年 
    代表者 : 横田 漠, 馬場 由成, 田辺 公子, 土手 裕, 大榮 薫, 宮武 宗利, 佐藤 努, 瀬崎 満弘
     
    我々は、バングラデシュにコミュニティ用砒素除去装置GSF(Gravel Sand Filter)をこの3年間に4基稼動させ、砒素除去性能をチェックしながら、その設計基準を確立してきた。GSFは砂利槽と砂槽からなるが、砒素除去のメカニズムは地下水中に高濃度に含有されている鉄分を本装置内で酸化し、砒素を3価鉄の共沈物として砂利槽内の砂利間隙中でトラップするものである。砒素除去に当たってはバッキ、砒素と鉄の接触時間およびリンなどの競合イオンの濃度がキーポイントとなる。特に、リン濃度の高い原水では鉄/砒素値を30(通常は10)となるように「鉄屑の付加」という基準を得ている。砒素除去装置から排出される汚泥は、砒素汚泥槽で沈殿処理され、その上澄み液は人工池に放流されている。沈殿汚泥の処分に関しては、汚泥のセメント固化処分の研究を行ってきた。溶出試験の結果、セメントを添加しない場合でも、汚泥中の砒素はその90%が汚泥中に閉じ込められるが、溶出濃度が0.05〜0.65mg/Lと試料によって環境基準値を超える場合がある。セメント添加量が2%の場合では0.05〜0.11mg/Lとわが国の第2溶出基準をクリアーする。pH=10.5〜10.9とアルカリ性でもあるので、遮水して貯蔵すれば問題ないと考えられる。汚泥タンクの上澄み液は人工池に放流されるが、そこで砒素の自然浄化処理を試みた。すなわち、池底土...
  • 文部科学省：科学研究費補助金(基盤研究(B))
    研究期間 : 2004年 -2006年 
    代表者 : 川西 琢也, 林 良茂, 佐藤 努, 鎌田 直人, 田崎 和江, 早川 和一
     
    1997年のナホトカ号事故で重度に汚染された海岸においても,海岸砂等については,多環芳香族炭化水素(PAHs)濃度はほぼバックグラウンドに近いところまで汚染が回復している.残留重油は岩の窪みなど一部に存在している程度である.ただし,残留重油中のPAHs濃度は,事故後2年までに約1/3に減少したものの,7年後にもほぼ同じ濃度であり,残留重油中のPAHは長期にわたって存在し続けることが分かった.2年間にわたるモニタリングの結果,沿岸域河口部の河川水と河口(表層)底質のPAHの分配に関しては,底質の有機物含有量が支配因子であり,有機物あたりの分配係数Kocはオクタノール分配係数Kowとよい相関があることが分かった.すなわち,線形自由エネルギーモデルが成立することが分かった.表層底質と河川水とのPAHsの交換速度は,近似的に平衡とできる程度に速いことが分かった.以上の知見から,ローカルな沿岸環境系において,例えば生物濃縮のように高濃度にPAHが蓄積するような可能性はきわめて低いと考えられる.実験室で,PAHsの底質への収着に対する溶存有機物質の影響を検討したが,溶存物質の影響は環数が多いほど大きくなること,現象の正確な記述には,溶存有機物質の底質への吸着も考慮すべきことが明らかになった.以上のように,沿岸部では,河川水あるいは海水と海岸の粒子等のメディア等の間では,物質の交換は,残留...
  • ベントナイト劣化の機構論的・速度論的研究
    受託研究
    研究期間 : 2002年
  • Mechanism and kinetics of bentonite degradation
    Funded Research
    研究期間 : 2002年
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2000年 -2001年 
    代表者 : 佐藤 努
     
    本研究では、海洋地殻の3割を越えるとされる超塩基性岩の変質により生成するマグネシウム炭酸塩、特に炭酸イオンをイオン交換反応により結晶構造内に取り込むことのできるハイドロタルサイト族鉱物の生成機構を明らかにし、地球表層部における炭酸イオン固定や二酸化炭素の循環に及ぼす影響を評価することを目的とした。そのため、昨年度の千葉県、徳島県、愛媛県、オマーンに引き続き、北海道幌満かんらん岩を調査し、地質調査および試料、(水、岩石、土壌)採取を行うとともに、雰囲気制御(二酸化他酸素分圧)鉱物変質実験装置による反応実験を継続した。その結果、超塩基性岩の風化や蛇紋岩化に伴う間隙水の高アルカリ化により、ハイドロタルサィト族鉱物は容易に生成し、溶存炭酸イオンはその生成によって固定化されることが判明した。また、生成時に他の陰イオンを取り込んだハイドロタルサイト族鉱物が形成しても、炭酸イオンに対する高い選択性から、生成後もイオン交換反応によって溶存炭酸イオンを固定可能であることが、雰囲気制御鉱物変質実験装置による実験から明らかとなった。間隙水の高アルカリ化は、亀裂に産するブルース石の風化溶解、または透輝石等の含Ca塩基性鉱物の蛇紋岩化によるCaの溶脱によるもので、Mg・Feかんらん岩の風化、溶脱のみでは高アルカリ化せず、単にMgの溶出と鉄酸化・水酸化物の生成にとどまることも判明した。以上のことから、今後、グローバルな炭素循環を考える場合、海洋底に露出して海洋風化に曝される超塩基性岩の分布やその蛇紋岩化の程度、海洋底下における極低温蛇紋岩化作用の有無、間隙に産するブルース石の含有量などの評価が重要であることが明らかとなった。
  • 有害陰イオンを含む廃水や汚染土壌の浄化法とその評価
    共同研究
    研究期間 : 2000年
  • 有害陰イオンの自然浄化作用
    共同研究
    研究期間 : 2000年
  • Remediation of soils and treatment of waste water with hazardous anions
    Cooperative Research
    研究期間 : 2000年
  • Natural attenuation of hazardous anion species
    Cooperative Research
    研究期間 : 2000年
  • 高アルカリ環境の地球化学
    共同研究
    研究期間 : 1992年
  • Geochemistry of hyperalkaline
    Cooperative Research
    研究期間 : 1992年

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