Experimental and Md Simulation of the Hydrophobic Adsorption Mechanism of P(Am-Maptac-Temac6) at Kaolinite/Water Interface

Abstract

The hydration characteristics of fine particles significantly influence the settling and dewatering of tailings. However, the current limited understanding of the micro-mechanisms governing the interactions between hydrophobic flocculants and fine particles hinders the optimization of tailings treatment technical. Through a combination of MD simulations, flocculation settling, and adsorption capacity analysis, the hydrophobic adsorption mechanism of P(AM-MAPTAC-TEMAc6) at the kaolinite/water interface was elucidated. Results suggested that hydrogen bonding and non-bond interactions synergistically drive the adsorption between P(AM-MAPTAC-TEMAc6) and the kaolinite surface. As the mass concentration of P(AM-MAPTAC-TEMAc6) increased, the hydrophobic and associative interactions between the molecular chains enhance the adsorption amount on kaolinite particles, leading to a notable decrease in the solution residual amount and the supernatant turbidity. Moreover, by reducing the density of the hydration film on the kaolinite surface decrease the compression layer thickness, thereby improving the dewatering performance of concentrated tailings. The fluorocarbon side chains of P(AM-MAPTAC-TEMAc6) enhance the hydrophobic adsorption capacity of cationic side chains in the surface water region. Simultaneously, the associative interactions of the molecular chains in the bulk water region promote enhanced diffusion and migration, thereby strengthening bridging mechanism between P(AM-MAPTAC-TEMAc6) and kaolinite particles, ultimately improving the settling and dewatering efficiency of the suspensions.

Keywords: Hydrophobic flocculation, Kaolinite, Adsorption behavior, Bridging mechanism