Influence of pyrite surface defects on xanthate adsorption: A density functional theory perspective

Abstract

Many scholars have studied the adsorption behavior of various ions and agent molecules on pyrite surfaces based on density functional theory (DFT) calculations, however, the adsorption behavior of pyrite by surface defects has been relatively less studied. In this study, we try to produce defects on the surface of pyrite by hydration and study them systematically. The effects of pyrite surface defects on the molecular adsorption of xanthates were investigated on the atomic scale by combining DFT calculations, and AFM observation methods, respectively. The results indicate that oxygen molecules can indirectly participate in hydration reactions and promote crystal defect generation. In addition, the absence of coordination intensifies the electron transfer of pyrite, which favors the formation of new coordination with xanthates, and the adsorption energy is also reduced. Defects lead to an increase in the number of xanthate molecules at the adsorption site, and the adsorption capacity is also enhanced. The adsorption morphology was analyzed by AFM measurements to confirm the DFT calculation results. The complex interfacial system of sulfide ores was investigated, and it was found that the hydration process of sulfide ores generates surface defects, which further promote xanthate molecules adsorption. The results extend the traditional electrochemical adsorption theory of sulfide ores and provide theoretical support for the study of the molecular dynamics adsorption process on the surface of sulfide ores.