DFT study on Hg0 adsorption over graphene oxide decorated by transition metals (Zn, Cu and Ni)

Abstract

Mercury emissions from coal-fired power plants are a major cause of severe environmental issues, and elemental mercury is the most difficult form to remove from combustion flue gases. Based on density functional theory (DFT) calculations, the adsorption effects of elemental mercury on primary and three transition metals (Zn, Cu and Ni)-decorated graphene oxides (GO) have been studied. The larger adsorption energies, smaller adsorption distances and stronger charge transfer demonstrate the combination of Hg0 atom on primary GO and ZnGO/CuGO/NiGO surfaces have a significant change from physical adsorption to chemical adsorption. The enhancement order of three modified metal elements for mercury removal is Zn < Cu < Ni, and the maximum values of adsorbed mercury atoms are 2, 3 and 3. Hence, this study exhibits that ZnGO, CuGO and NiGO have favorable mercury removal performance, among which NiGO has the best mercury capture capacity.