Molecular simulation of polyacrylamide types on flocculation performance in oily wastewater

Abstract

The severity of the problem of oily sewage has prompted in-depth research on the mechanism of flocculation treatment. Most of the existing simulation studies focus on the interaction of a single type of pollutant, flocculant or solution, and the simulation research on the complex pollution system of oily sewage is still insufficient. In this study, molecular dynamics (MD) simulations and density functional theory (DFT) calculations were used to explore the interaction mechanism between different types of polyacrylamide (PAM) and oil molecules. The results show that AM-DMDAA-BA exhibits the strongest electron transfer ability and the best flocculation performance due to its small energy level difference. 40 °C was determined to be the optimal temperature for the four PAM flocculation treatment of oily wastewater; Due to its positive charge and hydrophobic group, AM-DMDAA-BA has a stronger electrostatic adsorption and hydrophobic effect with oil droplet molecules. The adsorption effect of AM-DMDAA-BA and CPAM on oil droplet molecules was better than that of NPAM and APAM, which could effectively break the agglomeration state between oil droplets and form a stable floc structure. This study provides a theoretical basis and technical support for the flocculation treatment of oily wastewater.