Electrochemical oxidation of a typical PPCP wastewater with a novel high-efficiency PbO2 anode based on NCNSs and Ce co-modification: Parameter optimization and degradation mechanism

In this study, a novel NCNS-Ce-PbO2 electrode was prepared by electrodeposition method using the rare earth metal Ce and synthesized nitrogen-doped carbon nanosheets (NCNSs). Various characterization and electrochemical performance tests showed that the NCNS-Ce-PbO2 electrode possessed a denser surface and smaller grains than other NCNS-PbO2 and Ce-PbO2 electrodes, with more active surface sites and thus could generate more hydroxyl radicals. N, N-diethyl-m-toluamide (DEET) was selected as the model contaminant to evaluate the electrochemical performance of the novel NCNS-Ce-PbO2 electrode. The effects of initial pollutant concentration, current density, electrolyte concentration, and initial pH on the removal rates of DEET and chemical oxygen demand (COD) were investigated. Under optimal conditions, after degradation of 150 min, the removal rate of DEET and COD reached 100% and 80.52%, respectively. GC-MS was used to identify intermediate products in the degradation process. The degradation mechanism and possible degradation pathways of DEET with NCNS-Ce-PbO2 electrode were discussed. The good stability of the NCNS-Ce-PbO2 anode was confirmed by accelerated lifetime experiments.