Integration of antibacterial and photocatalysis onto polyethersulfone membrane for fouling mitigation and contaminant degradation

Biofouling is a significant constraint in the development of membrane filtration technology. In this study, Ag nanoparticles (AgNPs) were synthesized homogeneously in situ on the polyethersulfone (PES) membrane surface, and titanium dioxide (TiO2) photocatalytic agent was subsequently coated through the functional polydopamine intermediate layer. The Ag-TiO2-PDA/PES membrane presented enhanced hydrophilicity, attractive antibacterial ability, and photocatalytic performance. The AgNPs modification achieved 96% bacterial inactivation by using the E.coli DH5α as the model microorganism, and TiO2 provided a photocatalytic degradation ability to the membrane. The improved flux recovery of the Ag-TiO2-PDA/PES membrane, which was approximately 95% in the third cyclical filtration, revealed the efficient antifouling ability through AgNPs and TiO2 modification. The Ag-TiO2-PDA/PES membrane inhibited biofouling in dynamic filtration by AgNPs and degraded the irreversible fouling by TiO2 during the cleaning procedure. The combined modification of the PES membrane by AgNPs and TiO2 exhibited a synergistic effect on the improvement of antifouling properties. This study provides a multifunctional membrane design strategy by combining antibacterial and photocatalysis to improve membrane fouling resistance.