Speciation of iodine in solid environmental samples by iodine K-edge XANES: Application to soils and ferromanganese oxides
Speciation of iodine in solid environmental samples by iodine K-edge XANES: Application to soils and ferromanganese oxides
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DOI：
10.1016/j.scitotenv.2006.01.004
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发表时间：
2006-06-15
影响因子：
9.8
通讯作者：
Uruga, Tomoya
中科院分区：
文献类型：
--
作者：
Kodama, Sayuri;Takahashi, Yoshio;Uruga, Tomoya
建立了一种利用X射线吸收近边结构（XANES）分析固体材料中碘形态的方法。该方法用于环境样品中碘的形态（主要是无机碘）的鉴定。结果表明，碘离子和碘酸根离子在固体材料中吸附的XANES光谱可以通过碘离子和碘酸根离子在水中的光谱的线性组合来模拟。土壤和水之间的分配系数（Kd）得到独立的碘化物和碘酸盐，碘形态的基础上，在固相中，通过XANES，并在水相，通过HPLC-ICP-MS。结果发现，碘酸钾的Kd是大于碘化物的一个因素超过6，显示更可溶性的碘化物。结果表明，即使在碘的Eh-pH图的碘稳定域内的条件下，将碘化物注入土壤-水系统中，也可以在土壤中形成碘酸盐。这是由于碘酸盐对固体表面的亲和力比碘化物高得多。在不同含水饱和度或不同Eh条件下的土壤样品中，随着Eh的降低，水中碘的含量增加，从而导致土壤水中溶解态总碘含量增加。使用XANES的形态分析方法也适用于自然土壤样品和海洋铁锰氧化物中的碘。有人建议，碘K-边XANES是一个很有前途的工具，用于确定天然固体样品中的碘化物/碘酸盐的比例，这有助于更好地了解碘在地球表面的行为。(c)2006 Elsevier B. V.保留所有权利。
A method was developed for speciation of iodine in solid materials using X-ray absorption near-edge structure (XANES). This method was used to identify the iodine species (mainly inorganic iodine) in environmental samples. It was shown that the XANES spectra of iodide and iodate sorbed within solid materials can be simulated by the linear combination of the spectra of iodide and iodate ions in water. The distribution coefficient (K-d) between soil and water was obtained independently for iodide and iodate, based on iodine speciation both in the solid phase, by XANES, and in the aqueous phase, by HPLC-ICP-MS. It was found that the Kd of iodate is larger than that of iodide by a factor of more than six, showing the more soluble nature of iodide. It was suggested that iodate can form in soil even when iodide is injected into the soil-water system under conditions within the iodide-stable field of the Eh-pH diagram of iodine. This is caused by the much higher affinity of iodate for solid surfaces than iodide. In soil samples under various water saturation conditions, or various Eh conditions, the iodide fraction in water increases with decreasing Eh, which results in an increase in the dissolved total iodine fraction in soil water. The speciation method using XANES was also applied to iodine in a natural soil sample and marine ferromanganese oxides. It is suggested that iodine K-edge XANES is a promising tool for determining the iodide/iodate ratio in natural solid samples, which contributes to better understanding of the behavior of iodine at the Earth's surface. (c) 2006 Elsevier B.V. All rights reserved.