Experimental and MD simulation of the hydrophobic adsorption mechanism of P(AM-MAPTAC-TEMAc6) at kaolinite/water interface

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 of P(AM-MAPTAC-TEMAc6) onto the kaolinite surface. As the mass concentration of P(AM-MAPTAC-TEMAc6) increased, the hydrophobic and associative interactions between the molecular chains enhanced the adsorption amount on kaolinite particles, leading to a notable decrease in the solution residual amount and the supernatant turbidity. P(AM-MAPTAC-TEMAc6) improved the dewatering performance of concentrated tailings by reducing the hydration film density on kaolinite surfaces, thus decreasing the compression layer thickness. 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 the bridging mechanism between P(AM-MAPTAC-TEMAc6) and kaolinite particles, ultimately improving the settling and dewatering efficiency of the suspensions.