Soheil Dadari, Bita Shirvani, Zahra Fadaei, Negin Ghaemi, Hamid Rajabi, John Bridgeman
• UV-grafting of green ZnO/Bentonite creates a novel multifunctional PES membrane. • Optimised M2 rejects amoxicillin and cephalexin at ∼99 % with high flux. • Visible-light activation enables 92.4% COD removal on real pharmaceutical effluent. • Antibacterial inhibition exceeds 95% against E. coli and Staphylococcus aureus. Pharmaceutical residues in wastewater pose a significant global threat due to their persistence and their role in contributing to antimicrobial resistance. This study presents a novel, sustainable nanofiltration membrane designed for advanced treatment of pharmaceutical wastewater. We utilized an eco-friendly UV-grafting technique to immobilize green-synthesized zinc oxide nanoparticles, anchored on acid-activated bentonite (ZnO-NPs/AAB), onto the surface of a polyethersulfone (PES) membrane. This approach is the first to combine these specific green components and fabrication methods. The resulting multifunctional membranes demonstrated significantly improved hydrophilicity, antifouling properties, and filtration performance. Characterisation by FTIR and EDAX confirmed successful surface modification. The optimized membrane, M2, UV-grafted with 0.06 wt% ZnO-NPs/AAB achieved outstanding removal efficiencies for amoxicillin trihydrate and cephalexin monohydrate (>99 %) and high degradation of organic pollutants from real pharmaceutical wastewater, with COD removal exceeding 92 % under visible light. Moreover, the membrane displayed potent antibacterial activity (>96 % inhibition of E. coli and S. aureus ), highlighting strong resistance to biofouling. Enhanced performance results from the synergy of photocatalysis, adsorption, size exclusion, and electrostatic interactions. This work presents a scalable and environmentally responsible approach for fabricating high-performance membranes that simultaneously address both chemical and microbial contaminants in wastewater.