Synthesis and Flotation-Flocculation Properties of Polyether Monoamine-Grafted Poly[N-(3-Dimethylaminopropyl) Methacrylamide]

The highly efficient air flotation hydrocyclone separation technology has been gradually promoted and applied. However, the performance of flocculant reported in the literature needs improvement. In this study, a novel flocculant was synthesized using poly[N-(3-dimethylaminopropyl)methacry] (PDPM) and polyether monoamine (PMA) as the main raw materials. The synthesis conditions of the flocculant were optimized based on the oil removal rate. It was found that when PMA M-2095 was used, the resulting product, Cl-0.4-P-0.2-2095, exhibited the best flotation-flocculation oil removal performance. At a dosage of 20 mg/L and a treatment time of 7 min, the oil removal rate of Cl-0.4-P-0.2-2095 reached 90.63%, which was 31.7% higher than that of the reported flocculant. Mechanistic investigations, including measurements of surface tension, interfacial tension, zeta potential, and interfacial elastic modulus, as well as oil-coated bubble experiments, revealed that Cl-0.4-P-0.2-2095 adsorbs onto the surfaces of bubbles and oil droplets. This adsorption enhances the collision and adhesion efficiency between bubbles and oil droplets, thereby improving the flotation-flocculation oil removal performance. This study provides a novel treatment agent for the efficient treatment of produced water from offshore oilfields.