Photocatalytic self-cleaning PVDF membrane modified with NM88B@TiO2 exhibits excellent anti-fouling and separation capabilities

The development of photocatalytic self-cleaning membranes represents a promising strategy for addressing membrane fouling in dye wastewater treatment. NH 2 -MIL-88B(Fe) (NM88B) possesses excellent chemical stability, hydrophilicity and inherent photocatalytic activity, its practical application is limited by the low carrier mobility and the rapid recombination of photogenerated electron-hole pairs. In this experiment, NM88B@TiO 2 was synthesized by in-situ growth method, and was constructed to enhance charge separation and photocatalytic efficiency, and then NM88B@TiO 2 /polyvinylidene fluoride (PVDF) mixed matrix membranes (MMMs) were fabricated using the non-solvent induced phase separation (NIPS) method. The loading capacity of NM88B@TiO 2 could reach up to 2 %. The optimal membrane has a porosity of 86.02 %, which is 63 % higher than that of the original PVDF (52.78 %). The pure water permeability of the optimal membrane is 52.87 L·m −2 ·h −1 ·bar −1 , 2.5 times that of the original membrane. The water contact angle decreased from 85.6° to 40.4°, making the membrane highly hydrophilic. In the anti-BSA fouling experiment, the flux recovery rate (FRR) of the optimal membrane still maintained above 75 % even after 6 cycles, demonstrating excellent antifouling ability and also reusability. Moreover, the membrane showed a good rejection rate for various dyes. Additionally, this membrane exhibited excellent photocatalytic self-cleaning ability. After 7 photocatalytic self-cleaning cycles, the membrane permeability basically returned to its initial state, and the membrane maintained a good CR rejection rate (>90 %). During the continuous 72-hour CR filtration process, the permeability and rejection rate remained unchanged. These results highlight the potential of the NM88B@TiO 2 modified PVDF membrane as a photocatalytic self-cleaning membrane for treating wastewater containing dyes.