Bioinspired Modification of Polyethersulfone Membranes Using Aluminum Oxide Hydroxide–Tannic Acid Hybrid Nanoparticles for Enhanced Water Filtration Performance

ABSTRACT Polyethersulfone (PES) membranes, while widely used in ultrafiltration, are hindered by their inherent hydrophobicity and susceptibility to fouling. This study investigates the incorporation of aluminum oxide hydroxide–tannic acid (AlOOH–TA) hybrid nanoparticles into PES membranes via phase inversion to enhance hydrophilicity and antifouling behavior. The AlOOH–TA hybrid introduces abundant hydroxyl and phenolic groups that promote hydration layer formation and reduce foulant adhesion, while alumina contributes structural reinforcement. The modified membranes were characterized using SEM, FTIR, contact angle, and porosity analyses to correlate surface and structural changes with filtration performance. The optimized membrane (M4) achieved a pure water flux of 37.71 L·m −2 ·h −1 and a contact angle of 56.7°, representing a 38.95% flux improvement and enhanced surface wettability compared to pristine PES. In humic acid filtration, M4 exhibited a rejection efficiency of 61.4% and a flux recovery ratio (FRR) of 99.72%, confirming its excellent antifouling and reusability performance. These findings demonstrate that AlOOH–TA hybrid incorporation effectively improves membrane hydrophilicity and antifouling resistance through synergistic chemical and structural modification.