X-ray absorption spectroscopy study of H2S sorption on iron-rich soil: characterization of iron-sulfur species.

Iron-rich soil after sorption of H(2)S was characterized using X-ray absorption near-edge structural (XANES) and extended X-ray absorption fine structure spectroscopy (EXAFS) for determination the possible products in the present work. EXAFS revealed that the main Fe-S species in the sulfided sample were FeS (troilite) and Fe(1-x)S (pyrrohotite). Iron in the sulfided sample was found to possess a Fe-S bond distance of 2.36 A and a Fe-O bond distance of 1.72 A in the Fe-K-edge spectra whereas the Fe-S bond distance of 2.25 A was determined in the sulfur K-edge spectra. In the second shells, the bond distance of Fe-O-Si or Fe-O-Al with 3.28 A was also observed. No FeS2 (pyrite) was included in the sulfided sample. The formation of Fe(1-x)S was probably attributed to the presence of Fe(3)O(4), a type of spinel structure with a lattice deficiency.