Antimony(V) Incorporation into Synthetic Ferrihydrite, Goethite, and Natural Iron Oxyhydroxides
Antimony(V) Incorporation into Synthetic Ferrihydrite, Goethite, and Natural Iron Oxyhydroxides
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DOI：
10.1021/es903901e
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发表时间：
2010-05-15
影响因子：
11.4
通讯作者：
Sakata, Masahiro
中科院分区：
文献类型：
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作者：
Mitsunobu, Satoshi;Takahashi, Yoshio;Sakata, Masahiro
在这项研究中，我们研究了本地结构的锑物种在合成锑钒共沉淀和吸附的水铁矿和针铁矿，这是常见的铁（III）的羟基氧化物在环境中，在不同的Sb/Fe摩尔比扩展X射线吸收精细结构（EXAFS）分析。EXAFS分析表明，锑钒吸附在水铁矿和针铁矿形成的内球表面络合物在pH值为7.5。在共沉淀的水铁矿和针铁矿的EXAFS谱中，一些光谱特征与吸附样品中的光谱特征有显著不同。EXAFS模拟表明，这种差异是由于在共沉淀样品中Fe原子与Sb原子的配位数较大，表明Sb-V在水铁矿和针铁矿中的结构掺入（异价取代）。锑-V的掺入到结构中也证实了天然铁（III）的羟基氧化物在受污染的土壤附近的Sb矿山尾矿，使用μ-EXAFS。这项研究直接提供了第一个证据的结构纳入锑钒铁（III）氧化物结构。我们的研究结果是很重要的了解锑在水生环境中的命运，因为通过这样的替代纳入固体的元素的行为是没有很大的影响水生因素，如pH值和离子强度，因为从水相的金属（loid）离子的隔离。
In this study, we investigated local structures of Sb species in synthetic Sb-V-coprecipitated and -adsorbed ferrihydrite and goethite, which are common iron(III) oxyhydroxides in environment, at various Sb/Fe molar ratios by extended X-ray absorption fine structure (EXAFS) analyses. The EXAFS analyses showed that Sb-V is adsorbed on ferrihydrite and goethite by the formation of an inner-sphere surface complex at pH 7.5. In the EXAFS spectra of the coprecipitated ferrihydrite and goethite, some features of the spectra significantly differed from those in the adsorbed samples. The EXAFS simulation indicated that the difference is due to the larger coordination number of the Fe atom to the Sb atom in the coprecipitation samples, indicating a structural incorporation (heterovalent substitution) of Sb-V into ferrihydrite and goethite. The incorporation of Sb-V into the structure was also confirmed in natural iron(III) oxyhydroxides in contaminated soil near an Sb mine tailing using mu-EXAFS. This study directly provided the first evidence for the structural incorporation of Sb-V into the iron(III) oxide structure. Our findings are important for understanding the fate of Sb in the aquatic environment because the behavior of the elements incorporated into solids by such a substitution is not greatly influenced by aquatic factors such as the pH and ionic strength because of isolation of the incorporated metal(loid) ions from the aqueous phase.