Self-Cleaning HGN–CoTiO₃-TiO₂-PVDF Ultrafiltration Membranes for Antibiotic Removal and Fouling Mitigation in Wastewater Treatment

Antibiotic residues released from hospital effluents contribute to environmental contamination and accelerate antimicrobial resistance, highlighting the need for membrane technologies capable of simultaneously achieving pollutant removal and fouling mitigation. Herein, a multifunctional photocatalytic ultrafiltration membrane was developed by incorporating a holey graphene (HGN)–CoTiO₃/TiO₂ heterostructure into a poly(vinylidene fluoride) (PVDF) matrix through the non-solvent induced phase separation (NIPS) method. The HGN–CoTiO₃/TiO₂ heterostructure exhibited enhanced optical absorption together with improved charge separation and interfacial electron transport, resulting in superior photocatalytic activity toward tetracycline (TCL) and ciprofloxacin (CFL). The optimized heterostructure achieved 99% TCL and 96% CFL removal in antibiotic-spiked hospital wastewater under 365 nm UV irradiation. Incorporation of HGN–CoTiO₃/TiO₂ into PVDF significantly improved membrane hydrophilicity and surface charge, leading to ~ 98% humic acid rejection together with excellent antifouling behaviour and UV-assisted flux recovery. Under static photocatalytic conditions, the optimized membrane (MTG2) achieved approximately 97–98% TCL removal, demonstrating effective photocatalytic self-cleaning. The enhanced membrane performance is attributed to the synergistic combination of membrane separation and photocatalytic oxidation enabled by the HGN–CoTiO₃/TiO₂ heterostructure. This work provides an effective strategy for developing photocatalytic self-cleaning ultrafiltration membranes for the treatment of antibiotic-contaminated hospital wastewater.