| Comparison of antimony behavior with arsenic under various soil redox conditions |
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| 作者姓名： | Satoshi Mitsunobu Teppei Harada Yoshio Takahashi |
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| 作者单位： | Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan |
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| 摘 要： | Antimony （Sb） is a toxic element and belongs to group 15 of the periodic table, under arsenic （As）. The geochemical behavior of Sb in the environment is still largely unknown. Since the behavior of Sb in the environment depends on its oxidation state, Sb analysis in environmental samples requires quantitative measurement of Sb （Ⅲ） and Sb （Ⅴ）. The aim of this study is the speciation of Sb in both solid and water phases to understand the reaction and dynamics of Sb in soil-water system. Accordingly, we employed X-ray absorption fine structure （XAFS） analysis to determine the Sb and As species in soil in laboratory and natural systems, while we also determined the oxidation states in soil water by the conventional HPLC-ICP-MS method. Natural soil and soil water samples containing Sb and As were collected around the Ichinokawa mine pithead, Ehime, Japan. To observe the species under various redox conditions, the soil and soil water samples were collected at four depths. Soil containing Sb and As were incubated for 7 days at 25℃ to observe their oxidation states under various redox condition by changing the total amount of water in the soil. Antimony K-edge XAFS spectra were measured at the beamline BL01B 1 at SPring-8 （Hyogo, Japan） and K-edge XAFS spectra of As, Fe, and Mn at the beamline BL12C in Photon Factory, KEK （Thukuba, Japan）. In the natural soil-water system, Sb was present exclusively as Sb （Ⅴ） over a wide redox range （from Eh=-140 to 360 mV; pH 8）, while As was present as a mixture of As （Ⅲ） and As （Ⅴ）. This trend was confirmed in the laboratory experiments. These results suggest that Sb （Ⅴ） is a very stable form in the environment and that Sb is oxidized under more oxic condition than As. Combining the results of Fe and Mn XAFS analyses and a positive correlation among Sb, As, and Fe abundances in the soil, the host phases of Sb and As in soil were Fe （Ⅲ） hydroxide. EXAFS analyses of Sb and As are also consistent with this fact. Under reducing conditions, the concentrations of As in the soil water increased whereas those of Sb decreased in both the natural and laboratory systems.
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| 关 键 词： | 锑 砷 氧化还原作用 土壤污染 环境控制 |
Comparison of antimony behavior with arsenic under various soil redox conditions |
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| Satoshi Mitsunobu Teppei Harada Yoshio Takahashi.Comparison of antimony behavior with arsenic under various soil redox conditions[J].Chinese Journal of Geochemistry,2006,25(B08):98-99. |
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| Abstract: | |
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| Keywords: | antimony arsenic XAFS HPLC-ICP-MS redox condition |
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