Photo-Fenton ceramic composite membrane with Ag-doped FeOOH film for synergistically enhanced dye removal

Membrane separation coupled with advanced oxidation is an effective method for organic pollutants removal in wastewater. Especially, composite membranes with immobilized catalysts can separate and degrade pollutants simultaneously, which could simplify the operation process. Herein, Ag-doped FeOOH film with visible light responsive property was prepared on a polydopamine (PDA)-modified ceramic ultrafiltration substrate (∼50 nm). XPS, FESEM, XRD and EDS analyses confirm the successful formation of FeOOH nanorods and Ag nanoparticles on the substrate surface. The pure water flux of the composite membrane is 138.1 L m−2 h−1 bar−1 when the molar ratio of Ag to Fe is 1:20 (5 % Ag@Fe-CM). In cross-flow filtration, the composite membrane obtains good removal efficiency of methylene blue (MB) through the synergistic effect of membrane adsorption, separation, and photo-Fenton degradation. When the H2O2 concentration is 10 mM, the composite membrane shows the highest removal efficiency (93.2 %) of MB, which is 17.7 % higher than that of the pure FeOOH decorated membrane. The Ag nanoparticles enhance the photo-Fenton catalytic activity of FeOOH. Moreover, after photo-Fenton reaction, the flux recovery of MB-contaminated composite membrane reaches 91.7 %, and the removal efficiency of MB remains above 88 % after four experimental cycles, indicating superior self-cleaning ability and reusability. This study provides a meaningful strategy to prepare photo-Fenton ceramic composite membrane, which has broad applications in organic wastewater treatment.