Computational insights into interactions between Hg species and α-Fe2O3 (0 0 1)

First-principle calculations based on Density Functional Theory were performed to investigate the binding mechanisms of mercury species on α-Fe2O3 (0 0 1) surface. This is crucial in demonstrating the contribution of α-Fe2O3 existing in fly ash for mercury removal. It has been determined that Hg0 is adsorbed on the α-Fe2O3 (0 0 1) surface with physisorption mechanism. The oxidized forms of HgCl and HgCl2 can be adsorbed on α-Fe2O3 (0 0 1) dissociatively or non-dissociatively. In the case of dissociative adsorption, a close examination of the energy diagram indicates that HgCl may be favorable for the adsorption of Cl and desorption of Hg. The dissociation of HgCl2 with the binding of Cl and HgCl on the surface is possibly the dominant interaction pathway.