Enhanced synergistic performance of nano-Fe0-CeO2 composites for the degradation of diclofenac in DBD plasma

Abstract

Dielectric barrier discharge (DBD) is an attractive advanced oxidation process (AOP) due to its operational convenience and environmental friendliness. However, DBD plasma suffers from relatively low energy utilization, which limits its commercial application. In this study, nano-Fe0-CeO2 is successfully synthesized and used for DBD plasma degradation of diclofenac (DCF). The results show that the nano-Fe0-CeO2 significantly enhances the removal of DCF. A DBD-Fe0-CeO2 system degrades 96.4% DCF within 10 min, which is higher than the DBD system alone (45.8%). The synergistic factor of the DBD system and nano-Fe0-CeO2 reaches 3.731. In addition, the composite catalyst shows ideal reusability. Substance activity and production experiments show that reactive oxygen species (ROS), especially OH, play a key role in the degradation of DCF. Nano-Fe0-CeO2 has synergistic effects with O3 and H2O2 and significantly promotes the generation of ROS in the DBD system. Based on the intermediates detected by liquid chromatography-mass spectrometry, a reasonable degradation pathway of DCF is proposed. Our findings are helpful for understanding the mechanism of DCF degradation by coupling nano-zero-valent-iron-based nanocomposites in a DBD system; they also provide an effective system for the treatment of refractory organic pollutants in water.