Hg oxidation reaction mechanism on Fe2O3 with H2S: Comparison between theory and experiments

A group of adsorption experiments were performed to clarify the mechanism of elemental mercury adsorption on Fe2O3 in the presence of H2S. The roles of H2S and Fe2O3 playing in the heterogeneous reaction were respectively discussed. A probable pathway of Hg0 adsorption on Fe2O3 with H2S was proposed in previous computational research. Corresponding experiments were designed to compare with theoretical results. The H2S adsorption experiments and subsequent temperature programmed desorption analysis of derived sample indicate that H2S can be adsorbed on the surface of Fe2O3, which is in accordance with the computational results. Significantly high Hg0 removal efficiency of H2S adsorbed Fe2O3 verifies the strong interaction between gaseous mercury and adsorbed sulfur species which is inferred in the theoretical study. Combining experimental and computational results together, the Eley-Rideal mechanism with H2S pre-adsorption can be determined.