Adsorption of phosphate by cancrinite in red mud: a first-principles study

Abstract

Cancrinite is the key substance that affects the adsorption effect of phosphate from red mud(RM) . Therefore, cancrinite in RM was modified to improve its adsorption performance. Based on density functional theory(DTF), this paper optimized the structure of cancrinite, the main component of red mud, modified the cancrinite with sodium dodecyl benzene sulfonate, and studied the surface wettability changes of cancrinite before and after modification through dynamics relaxation. The effects of wetting modification on the adsorption properties of cancrinite were studied by molecular dynamics simulation of radial distribution function, adsorption site , adsorption energy and mean square displacement. Research shows that modified cancrinite Surface wettability increased by 77%, also has more adsorption sites, adsorption energy is smaller, diffusion process is accelerated, so the adsorption capacity is stronger. This study lays a theoretical foundation for enhancing the adsorption of phosphate from wastewater by RM.

Keywords

• red mud
• cancrinite
• density functional theory
• molecular dynamics
• wettability
• adsorption