A nanopyrite/greigite composite was synthesized by reacting FeCl 3 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+2S 4) 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. © 2012 American Chemical Society.
Nanocomposite pyrite-greigite reactivity toward Se(IV)/Se(VI) / Charlet, L.; Kang, M.; Bardelli, F.; Kirsch, R.; Gehin, A.; Greneche, J. -M.; Chen, F.. - In: ENVIRONMENTAL SCIENCE & TECHNOLOGY. - ISSN 0013-936X. - 46:9(2012), pp. 4869-4876. [10.1021/es204181q]
Nanocomposite pyrite-greigite reactivity toward Se(IV)/Se(VI)
Bardelli F.;
2012
Abstract
A nanopyrite/greigite composite was synthesized by reacting FeCl 3 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+2S 4) 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. © 2012 American Chemical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
