Sequential anodic oxidation and cathodic electro-Fenton in the Janus electrified membrane for reagent-free degradation of pollutants

Abstract

Electrified membrane technologies have recently demonstrated high potential in tackling water pollution, yet their practical applications are challenged by relying on large precursor doses. Here, we developed a Janus porous membrane (JPEM) with synergic direct oxidation by Magnéli phase Ti₄O₇ anode and electro-Fenton reactions by CuFe₂O₄ cathode. Organic pollutants were first directly oxidized on the Ti₄O₇ anode, where the extracted electrons from pollutants were transported to the cathode for electro-Fenton production of hydroxyl radical (·OH). The cathodic ·OH further enhanced the mineralization of organic pollutant degradation intermediates. With the sequential anodic and cathodic oxidation processes, the reagent-free JPEM showed competitive performance in rapid degradation (removal rate of 0.417 mg L^-1 s^-1) and mineralization (68.7 % decrease in TOC) of sulfamethoxazole. The JPEM system displayed general performance to remove phenol, carbamazepine, and perfluorooctanoic acid. The JPEM runs solely on electricity and oxygen that is comparable to that of PEM relies on large precursor doses and, therefore, operation friendly and environmental sustainability. The high pollutant removal and mineralization achieved by rational design of the reaction processes sheds light on a new approach for constructing an efficient electrified membrane.

Keywords: Anodic oxidation; Electro-Fenton process; Electrocatalytic membrane; Mineralization; Water treatment.