Theoretical study of hydrocarbon functional groups on elemental mercury adsorption on carbonaceous surface

The interaction between Hg-0 and carbonaceous surface containing hydrocarbon functional groups (HFG) is investigated by DFT calculations. The carbonaceous surface is represented by a cluster model consisting of nine fused benzene rings. HFG is expressed by the molecular formulas of CxHy (x = 1, 2; y = 1, 2, 3...6). All possible approaches of HFG are carried out to evaluate the effect on mercury adsorption. The results indicate that the adsorption of HFG can increase the activity of its neighboring carbon atoms. In addition, the number of carbon atoms and hydrogen atoms on HFG has great influence on adsorption characteristics. The effect of HFG on Hg-0 adsorption on a carbonaceous surface is complicated. The mercury adsorption property depends on the adsorption position of mercury atom. When mercury atom is adsorbed by both HFG and carbonaceous surface, the mercury adsorption is determined by HFG, carbonaceous surface and carbon ring together. When mercury atom is only adsorbed by carbonaceous surface, the behaviors of neighboring and next-nearest neighboring carbon atoms on carbonaceous surface determine the mercury adsorption.