Combined DFT and XPS investigation of enhanced adsorption of sulfide species onto cerussite by surface modification with chloride

This study systematically investigates the enhanced adsorption of sulfide species onto cerussite by surface modification with chloride through density functional theory calculations and X-ray photoelectron spectroscopy (XPS) measurements. Calculation results demonstrate obvious differences in the surface structures and electronic properties of cerussite after HS- adsorption in the absence and presence of chloride species. Surface modification with chloride promotes the stable adsorption of HS- onto the cerussite surface, and the hybridization of Pb 6p orbital at the surface layer and S 3p orbital from HS- is enhanced. Moreover, the reactivity of cerussite surfaces is enhanced by the occurrence of new DOS peaks of Pb 6p and S 3p near the Fermi level and by the transfer of additional electrons between the bonding atoms in the presence of chloride. Meanwhile, Mulliken population and XPS analysis results indicate that a slight oxidation is involved in the interaction between sulfide species and cerussite surfaces because of the presence of disulfide and polysulfide in the sulfidization products. In addition, a higher proportion of disulfide and polysulfide relative to the overall S is exhibited in the presence of chloride, facilitating the sulfidization flotation of cerussite. (C) 2017 Elsevier B.V. All rights reserved.