Nanocomposite Pyrite鈥揋reigite Reactivity toward Se(IV)/Se(VI)

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• 作者：Laurent Charlet ; Mingliang Kang ; Fabrizio Bardelli ; Regina Kirsch ; Antoine G茅hin ; Jean-Marc Gren猫che ; Fanrong Chen
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：May 1, 2012
• 年：2012
• 卷：46
• 期：9
• 页码：4869-4876
• 全文大小：421K
• 年卷期：v.46,no.9(May 1, 2012)
• ISSN：1520-5851

文摘

A nanopyrite/greigite composite was synthesized by reacting FeCl₃ and NaHS in a ratio of 1:2 (Wei et al. 1996). Following this procedure, the obtained solid phases consisted of 30鈥?0 nm sized particles containing 28% of greigite (Fe²⁺Fe³⁺₂S₄) and 72% pyrite (FeS₂). Batch reactor experiments were performed with selenite or selenate by equilibrating suspensions containing the nanosized pyrite鈥揼reigite solid phase at different pH-values and with or without the addition of extra Fe²⁺. XANES-EXAFS spectroscopic techniques revealed, for the first time, the formation of ferroselite (FeSe₂) as the predominant reaction product, along with elemental Se. In the present experimental conditions, at pH 6 and in equilibrium with Se⁰, the solution is oversaturated with respect to ferrosilite. Furthermore, thermodynamic computations show that reaction kinetics likely played a significant role in our experimental system.