Development of high-performance polysulfone ultrafiltration membranes with enhanced permeability and antifouling properties via amino-functionalized TiO2 nanotube incorporation

This study investigates the development and performance of polysulfone (PSM)-based composite ultrafiltration membranes enhanced with titanate nanotubes (TNT) and amine-functionalized TNT (PSM-TNT@NH2) at varying levels (1 %, 3 %, 5 %, and 7 %). The addition of TNT and subsequent amine functionalization aimed to improve the membranes’ hydrophilicity, porosity, mechanical strength, antifouling properties, and filtration efficiency. Characterization by SEM, AFM, and contact angle measurements revealed that TNT and amine functionalization significantly enhanced surface roughness, hydrophilicity, and porosity, with optimal properties observed at 3 % and 5 % amine functionalization. TGA and XRD analyses confirmed structural stability and partial crystallinity from TNT, contributing to increased thermal resistance and mechanical robustness. Filtration tests demonstrated that PSM-TNT@NH2 membranes with 3 % and 5 % amine functionalization exhibited the highest water flux, enhanced rejection of organic contaminants such as humic acid (HA), bovine serum albumin (BSA), and sodium alginate (SA), and minimized fouling. These membranes achieved flux recovery ratios (FRR) close to 90 % after repeated cycles, with low irreversible fouling ratios (Rir) and reduced total fouling (Rt), indicating strong resistance to irreversible fouling and ease of cleaning. In contrast, excessive functionalization at 7 % led to slight performance declines due to pore aggregation and surface irregularities. Overall, the study demonstrates that the optimized PSM-TNT@NH2 membranes with 3 %–5 % amine functionalization provides an effective balance of high flux, antifouling capability, and structural stability, making them highly suitable for sustainable ultrafil- tration applications in water purification and wastewater treatment.