Study on reductive sorption of Se(IV,VI) onto pyrite with micro-XRF/XAS

Kitamura, Akira  ; Curti, E.*; Aimoz, L.*

A batch experiment was performed to investigate sorption of selenium(IV/VI) onto pyrite (FeS). Polished chips of natural pyrite were reacted with selenium(IV/VI) solutions with pH 89 for 2 months at 80 C under N atmosphere. Micro X-ray Fluorescence (-XRF) maps and Micro X-ray Absorption Spectra (-XAS) were collected in suitable sample holders flushed with inert gas. Crashed grains of natural pyrite were also used for comparison with pyrite chips. It was found that equivalent sulfur was dissolved to solutions after selenium sorption, sorption of selenium onto pyrite was highly heterogeneous, and both tetravalent and hexavalent selenium were reduced to selenium(0) after sorption onto pyrite.