Mechanism study on the synergistic degradation of DMAC wastewater by electrocatalytic carbon membrane reactor coupled with persulfate dual catalysis

In the presence of an electric field (EC), persulfate-mediated sulfate radicals ( SO 4 · − ) are an attractive wastewater treatment technology because they are cleaner and more complete. However, uncertainty in the degradation mechanism and high electrode cost limit the application of this technology. In this paper, a novel flat-plate multichannel carbon membrane (CM) coupled with persulfate (PDS) was used to construct an integrated system of electrocatalytic membrane reactor (ECMR) and for the efficient degradation of N , N -dimethylacetamide (DMAC). The system focused on the synergistic degradation mechanism of EC/CM/PDS and the removal efficiency of DMAC. The results indicated that cathodic degradation (92.4 %) was more effective than anodic degradation (11.3 %). Comparative experiments were conducted with different treatment processes, and the results indicated that the removal rate of DMAC by the EC/CM/PDS system was 6.4 and 10.5 times greater than that of the EC/CM and CM/PDS systems, respectively. In addition, the optimal operating parameters of ECMR were systematically investigated. The sulfate radicals ( SO 4 · − ), hydroxyl radicals ( ˙ OH ), and singlet oxygen ( 1 O 2 ) generated during the electrochemical cathodic activation of PDS by CM were confirmed to be the main reasons for the efficient degradation of DMAC through electron spin resonance (ESR) assay and quenching experiments. This work provides insights for analyzing the mechanism of action of EC/CM/PDS and designing efficient electrochemical advanced oxidation techniques to remove difficult-to-degrade organic pollutants.