XAFS characterization of mercury captured on cupric chloride-impregnated sorbents

X-ray Absorption Near-Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy were used to determine the mercury species formed as a result of the reaction of elemental mercury vapor with cupric chloride impregnated onto activated carbon. Oxidized mercury was found to be a dominant mercury species identified from XAFS analysis. Both XANES and EXAFS spectra indicated that Hg–Cl bonding is present from CuCl2- or HCl-impregnated sorbents, and HgCl2 is most likely to be formed rather than HgCl. In addition, the XAFS analysis results obtained for spent raw activated carbon sorbents prepared in nitrogen or oxygen carrier gas confirmed that chemisorption is likely the dominant adsorption mechanism of Hg(0) vapor. It is currently speculated from results from this and previous studies that if oxidized mercury is formed onto raw activated carbon, Hg(0) vapor is very likely to be bound to sulfur species.