Density functional study of Hg adsorption mechanisms on alpha-Fe2O3 with H2S

First-principle calculations based on the density functional theory are performed to clarify the Hg-0 adsorption reaction mechanism on an alpha-Fe2O3 surface with H2S in coal-utilizing facilities. Theoretical calculations based on the various adsorption mechanisms of H2S and Hg-0 on alpha-Fe2O3 are performed to investigate a realistic reaction pathway. The results demonstrate that the Eley-Rideal mechanism with Hg-0 adsorption on H2S/alpha-Fe2O3 surface is the most suitable reaction process, whereas the Mars-Maessen, Langmuir-Hinshelwood, and Eley-Rideal mechanisms with H2S adsorption on Hg-0/alpha-Fe2O3 surface are not possible in real reaction mechanisms. In addition, the potential energy diagram of H2S dissociation on alpha-Fe2O3 surface is provided. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.