Ethyl xanthate adsorption on different surfaces of jamesonite: A DFT study

Abstract

Adsorption of ethyl xanthate (EX) on jamesonite surfaces with exposing Pb, Fe and Sb (M1), Sb and Pb (M2) and Pb and Fe (M3) was investigated by DFT method. Adsorption energy of EX on M3 is the largest, −236.51 kJ/mol; and then M2, −189.62 kJ/mol; and M1, −65.84 kJ/mol in order. For EX adsorption on M1 surface, S1 and S2 of EX are bonded to Fe1 and Sb1 of jamesonite surface, respectively. However, high spin distribution of d-electrons of Fe2+ leads to the weak interaction between Fe1 and S1. Despite the high polarization rate of Sb3+, the interaction of Sb1 of M1 with S2 of EX is weak, which may be due to the coordination structure of Sb (3-coordination) and structure change of EX. Two sulfur atoms (S1 and S2) of EX are simultaneously bonded to Sb1 (2-coordination) of M2 surface for EX adsorption on M2, leading to the stronger interaction between EX and M2 than that between EX and M1. As for EX adsorption on M3, only S1–Pb1 bond is formed, but the far larger polarization rate of Pb2+ than Sb3+ leads to the stronger interaction between EX and M3 than that between EX and M2.