Investigation of the interaction between xanthate and kaolinite based on experiments, molecular dynamics simulation, and density functional theory

Abstract

Xanthate is widely used as a beneficiation reagent in mineral processing and plays an important role in subsequent wastewater disposal. Considering that kaolinite (Kaol) is a common gangue mineral in mining, understanding its interaction with xanthate is necessary. Herein, batch experiments involving Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), molecular dynamics (MD) simulation, and density function theory (DFT) are conducted to investigate the interactions between xanthate and Kaol surfaces. Results show that xanthate adsorption onto the Kaol surfaces fits well with the pseudo-first-order (PFO) and Langmuir models. The FTIR and XPS analyses suggest that xanthate interacts with Kaol surfaces through noncovalent interaction, and the MD simulations indicate that the xanthate molecule adsorbs onto the Kaol surfaces in a single layer. Moreover, the DFT results reveal that xanthate is more likely to be adsorbed onto the Kaol (001) surface than the (00ī) surface. Therefore, the presence of xanthate can influence the interaction between Kaol and the flocculant (i.e., polyacrylamide) during wastewater treatment because xanthate can occupy some of the active sites on the Kaol surface.