Objective To address the environmental contaminations and safety risks of oily wastewater in oil fields, this study investigates the influence of the sequence structure of copolymers of acryloyloxyethyl dimethyl benzyl (DABC) and methyl acrylate (MA) on flotation performance, and guides the development of efficient cationic polyacrylate flotation agents.

Method Using triblock P(DABC-b-MA-b-DABC), diblock P(DABC-b-MA), and random P(DABC-co-MA) as the study objectives, the oil removal performances were evaluated by flotation experiment. Interfacial tension measurements, zeta potential analysis, oil droplet-droplet interaction force quantification, dissipative particle dynamics (DPD) simulations, and oil droplet-air bubble adhesion and drainage time measurements were conducted to systematically analyzed the influence of copolymer sequence structures on oil removal mechanisms.

Result Cationic polyacrylate had better flotation oil removal effect than conventional flotation agents, and it was found for the first time that the sequence structure of DABC-MA copolymer had a key influence on its flotation oil removal performance and flotation microscopic process. Compared with random copolymers, block copolymers had better performance and shorter drainage time when oil droplets and bubbles adhere under the action of block copolymers, which led to better flotation oil removal performance of block copolymers (increasing oil removal rate by 12-32 percentage points). Triblock P(DABC-b-MA-b-DABC) had the best performance in promoting oil droplet coalescence and oil droplet bubble adhesion, and the best oil removal efficiency (oil removal rate of 93.9%).

Conclusion The triblock DABC-MA copolymer significantly improves flotation oil removal efficiency through sequence structure optimization, providing a safe and environmentally friendly new technology solution for oily wastewater treatment.