Photocatalytic degradation of polyacrylamide by rGO@Fe3O4/Cu2O@ZnO magnetic recyclable composites

Abstract In oilfield produced water, polyacrylamide (PAM) is a kind of organic polymer, which may gradually degrade to produce a large number of acrylamide (AM) monomer, and cause great damage to the peripheral nervous system of human and animals. In order to improve its removal efficiency, rGO@Fe3O4/Cu2O@ZnO magnetic composites with strong hydrophobicity, high photocatalytic performance and recyclability was prepared. The degradation process of PAM on composites photocatalyst was studied by simulating the sunlight irradiation, and the magnetic recovery performance and photocatalytic stability of composite were explored. Finally, the photocatalytic degradation mechanism of rGO@Fe3O4/Cu2O@ZnO composite was discussed by free radical capture experiment. The results showed that the highest photocatalytic degradation efficiency was 97.3% when the mass ratio of GO@Fe3O4 and Cu2O@ZnO was 1:5, the dosage of rGO@Fe3O4/Cu2O@ZnO was 0.6 g L−1, pH value was 7 and the initial concentration of PAM was 100 g L−1. After four cycles, the magnetic recovery and degradation efficiency of PAM can still up to 91.3% and 81%, respectively, which both meet the needs of magnetic recovery and photocatalysis. In addition, according to the free radical capture experiment, the main active species was superoxide radical (·O2−). This work provides a strategy for designing magnetic composites with hydrophobic and high catalytic for photodegradation of organic pollutants.