Comparison of antimony behavior with that of arsenic under various soil redox conditions
Comparison of antimony behavior with that of arsenic under various soil redox conditions
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DOI：
10.1021/es060694x
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发表时间：
2006-12-01
影响因子：
11.4
通讯作者：
Takahashi, Yoshio
中科院分区：
文献类型：
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作者：
Mitsunobu, Satoshi;Harada, Teppei;Takahashi, Yoshio
采用X-射线吸收精细结构(XAFS)光谱分析方法，测定了尾矿(日本爱媛Ichinokawa矿)土壤样品和实验室土壤-水系统中Sb和As的氧化态和主相。采用高效液相色谱-等离子体质谱联用技术对土壤水中的Sb和As进行形态分析。在Ichinokawa土壤水系统中，Sb在较宽的氧化还原范围内(Eh=360~-140 mV，pH 8)仅以氧化形式Sb(V)存在，而As则以As(III)和As(V)的混合物形式存在。这一发现在实验室实验中得到了证实。这些结果表明，Sb(V)在环境中是一种非常稳定的形式，Sb在比As更负的Eh处被氧化。结合Fe、Mn XAFS分析结果和土壤中Sb、As、Fe丰度之间的正相关关系，认为土壤中Sb、As的寄主相为Fe(III)氢氧化物。对Sb和As的XAFS分析也与这一发现一致。在还原条件下，无论是Ichinokawa系统还是实验室系统，土壤水中As的浓度都增加了，而Sb的浓度都降低了。这表明这种反差行为主要是由Sb和As的不同氧化还原性质控制的。
The oxidation states and host phases of Sb and As in soil samples of mine tailing (Ichinokawa mine, Ehime, Japan) and in laboratory soil-water systems were determined by X-ray absorption fine structure (XAFS) spectroscopy. HPLC-ICPMS was used for speciation of Sb and As in soil water. In the Ichinokawa soil water system, Sb was present exclusively as the oxidized form, Sb(V), over a wide redox range (from Eh = 360 to - 140 mV, pH 8), while As was present as a mixture of As(III) and As(V). This finding 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 at more negative Eh 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. XAFS analyses of Sb and As are also consistent with this finding. Under reducing conditions, the concentration of As in the soil water increased whereas that of Sb decreased in both the Ichinokawa and laboratory systems. This suggests that this contrasting behavior is controlled mainly by the different redox properties of Sb and As.