Nanocomposite Pyrite–Greigite Reactivity toward Se(IV)/Se(VI)

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 30–50 nm sized particles containing 28% of greigite (Fe2+Fe3+ 2S4) and 72% pyrite (FeS2). Batch reactor experiments were pe...

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Veröffentlicht in:Environmental science & technology 2012-05, Vol.46 (9), p.4869-4876
Hauptverfasser: Charlet, Laurent, Kang, Mingliang, Bardelli, Fabrizio, Kirsch, Regina, Géhin, Antoine, Grenèche, Jean-Marc, Chen, Fanrong
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Sprache:eng
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Zusammenfassung: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 30–50 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–greigite 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.
ISSN:0013-936X
1520-5851
DOI:10.1021/es204181q