Organic-inorganic composite ultrafiltration membrane with anti-fouling and catalytic properties by in-situ co-casting for water treatment

Organic-inorganic composite membranes have received much attention for superior water-treatment performance, where manipulating distribution of inorganic nanoparticles in membrane matrix remains a great challenge. Therefore, an in-situ co-casting was developed to modulate distribution of nanoparticles in membrane matrix for preparing multifunctional dual-layer manganese dioxide-polyvinylidene fluoride (MnO₂-PVDF) composite ultrafiltration membrane. Results showed MnO₂-PVDF membranes possessed apparent bi-layer structure and nanoparticles were distributed uniformly on the surface and upper layer. Such a configuration improved hydrophilicity with a maximum pure water permeance of 1012.97 L/m²·h·bar and displayed excellent mechanical strength. From anti-fouling tests, 7.5 wt% MnO₂-PVDF membrane presented the highest flux recovery of 83.2%, and low fouling propensity in either bovine serum albumin (BSA) solution or secondary effluent. The enhanced anti-fouling resulted from less attractive or even repulsive interactions between MnO₂-PVDF membranes and foulants. Furthermore, the MnO₂-PVDF membrane could accomplish ∼100.0% water flux recovery by a facile peroxymonosulfate (PMS) cleaning, following BSA fouling. Similarly, the catalytic capability of MnO₂-PVDF membrane for PMS was evidenced through the removal of various organic pollutants. In long-term operation, the composite membrane displayed excellent stability and low Mn ion leaching. Our results provide a promising route for structural regulation and development of organic-inorganic composite membranes for water treatment.