An EPMR for efficient treatment of DMAc-containing wastewater: Mutual promotion of electro-peroxone process and membrane reactor

Conventional electro-peroxone (EP) systems suffer from inefficient mass transfer that restricts the interfacial interaction between electrogenerated H 2 O 2 and dissolved O 3 . Herein, a novel EP membrane reactor (EPMR) was constructed by integrating O 3 aeration with permeable carbon membrane (CM) as both cathode and anode. The CM cathode (working electrode) has a porous structure and excellent electrical conductivity, allowing O 3 /O 2 -containing wastewater to flow through while occurring EP process. The water treatment performance was systematically evaluated through degradation of N, N-dimethylacetamide (DMAc) as the target pollutant. At a condition of 2.0 V applied voltage, 10 g L −1 Na 2 SO 4 electrolyte concentration, a permeation flux of 200 L m −2  h −1 , and an initial DMAc concentration of 100 mg L −1 , the EPMR system achieved a significantly higher chemical oxygen demand (COD) removal rate (59.1 %) compared to the conventional ozonation (19.70 %) and electrocatalysis (6.35 %). In the flow-through EPMR system, the yield of H 2 O 2 at 120 min was 16.77 mg L −1 , which is 9.64 times that of the flow-by mode (1.74 mg L −1 ). Meanwhile, the O 3 mass transfer coefficient reached 0.8561 min −1 , which was higher than flow-by (0.2439 min −1 ) modes, respectively. Electron spin resonance (ESR) analysis showed that the •OH contributed to approximately 40 % of COD removal in EPMR. The EP process and MR show a good mutual promotion effect. Specifically, CM cathode improves the mass transfer of O 2 and increases the production of H 2 O 2 via the oxygen reduction reaction (ORR). The increase in H 2 O 2 production, in turn, promotes the consumption of dissolved O 3 through the EP process and improves the gas–liquid mass transfer of O 3 , resulting in high DMAc degradation efficiencies. This study proposed an efficient method for DMAc wastewater treatment.