Degradable cationic clarifiers based on ester bonds for treating wastewater produced from polymer flooding

Polymer-contained oily sludge is inevitably produced when the oily wastewater produced from polymer flooding (OWPF) is treated by a cationic polymer clarifier, and it severely affects oilfield production. This study designed a novel degradable cationic clarifier (DCC) based on the ester bond and prepared it in light of the poly(β-amino ester) used in the area of generic material delivery. First, the copolymer of N -[3-(dimethylamino) propyl] methacryamide (DMAPMA) and diallylamine (PDMAPMA-NH) were synthesized by radical copolymerization. Then, the DCC was prepared by Michael addition between PDMAPMA-NH and poly(ethylene glycol) diacrylate. The synthesis conditions of DCC were investigated, and a DCC with excellent flocculant performance and good degradability was successfully prepared. At 70°C, both the degradations of DCC and the water-insoluble polymer complex formed by DCC and the polymer used for polymer flooding can be completed in 10 h, which is beneficial for the self-disappearance of the polymer-contained oily sludge. The flocs formed by DCC were observed at different times, and the results confirmed that the flocs can change to an oil film and that the polymer-contained oily sludge cannot exist for a long time. This study provides inspiration for OWPF treatment and expands the new application for poly(β-amino ester).