Antifouling performance and mechanisms in an electrochemical ceramic membrane reactor for wastewater treatment

Membrane fouling remains as a critical issue limiting the widespread applications of membrane-based technologies for water and wastewater treatment. In this work, an electrochemical ceramic membrane reactor (ECMR), in which ceramic membrane with built-in Ti mesh acted as cathode/filter and Ti/SnO2-Sb-Ce as anodes, was developed for mitigating membrane fouling during wastewater treatment. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) of Ti/SnO2-Sb-Ce electrode demonstrated favorable electrochemical properties. Filtration tests with influent wastewater containing 50 mg/L sodium alginate (SA) showed that TMP increase rate for the ECMR was decreased by 23.9-72.7% compared to the control, dependent on the exertion modes of electric field in this reactor. It was found that all the oxidants contributed to the enhanced antifouling performance of the ECMR due to in-situ membrane cleaning effects while the hydrogen peroxide and active chlorine (Cl-T) played a more important role compared to superoxide anions and hydroxyl radicals. SA was oxidized to a smaller size after reacting with reactive oxygen species (ROS) and Cl-T, benefiting the mitigation of membrane fouling in ECMR.