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 Hg-0 over graphene were investigated using density functional theory method. The results showed that all the adsorptive effect of SO2, NO, and Hg-0 were caused by physical interaction. The adsorptive energy of SO2 was the highest, and the adsorptive energy of Hg-0 was the lowest. SO2 could be preferentially adsorbed and removed. NO/SO2 and Hg-0 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 Hg-0 + SO2 + NO to chemical adsorption due to the interaction among Hg-0, SO2, and NO. As such, this study provides a theoretical insight for future application and development. Graphical abstract NO/SO2 and Hg-0 had the mutual promotion effect for simultaneous adsorption. SO2 and NO had the mutual inhibition effect for simultaneous adsorption.