Theoretical study on simultaneous removal of SO2, NO, and Hg0 over graphene: competitive adsorption and adsorption type change.

In this work, the influence of competitive adsorption and the change of charge transfer for simultaneous adsorption removal of SO2, NO, and Hg0 over graphene were investigated using density functional theory method. The results showed that all the adsorptive effect of SO2, NO, and Hg0 were caused by physical interaction. The adsorptive energy of SO2 was the highest, and the adsorptive energy of Hg0 was the lowest. SO2 could be preferentially adsorbed and removed. NO/SO2 and Hg0 had the mutual promotion effect for simultaneous adsorption over graphene surface. SO2 and NO had the mutual inhibition effect for simultaneous adsorption over graphene surface. Compared with single molecular adsorption, the adsorption type of bi-molecular adsorption did not change. However, the simultaneous adsorption changed the adsorption type of Hg0 + SO2 + NO to chemical adsorption due to the interaction among Hg0, SO2, and NO. As such, this study provides a theoretical insight for future application and development. Graphical abstractNO/SO2 and Hg0 had the mutual promotion effect for simultaneous adsorption. SO2 and NO had the mutual inhibition effect for simultaneous adsorption.