Unveiling Adsorption Mechanisms of Elemental Mercury on Defective Boron Nitride Monolayer: A Computational Study

Abstract

The control of mercury in flue gas is challenging, especially that of elemental mercury (Hg0). Recently, many researchers have focused on various mercury removal technologies. Here, by performing density functional theory (DFT) calculations, we systematically studied the adsorption of Hg0 on several experimentally available hexagonal boron nitride (h-BN) nanosheets with no defects, nitrogen vacancies (VN), boron vacancies (VB), and both nitrogen and boron vacancies (VN+B) as well as their structures and electronic properties. Our calculation results show that the presence of VN, VB, and VN+B enhances the adsorption energies of Hg0 by 9, 45, and 214 kJ/mol, respectively. Moreover, a more negative potential at the VB and VN+B sites makes the h-BN-VB and h-BN-VN+B surfaces more reactive than those of h-BN and h-BN-VN. The partial density of states analysis reveals that the Hg atom interacts firmly with surface B or/and N atoms through orbital hybridization. The trend of the equilibrium constant implies that ...