Effects of PVA/TiO2 Composite Hydrogel-Modified PES Ultrafiltration Membranes on Antibiotic Removal Performance and Membrane Fouling Behavior.

To improve the hydrophilicity and antibiotic retention of conventional polyethersulfone (PES) ultrafiltration membranes, a PVA/TiO2 composite hydrogel-modified PES membrane was prepared by hydrogel coating and in situ TiO2 embedding. Its removal of common antibiotics and antibiotic resistance genes (ARGs), as well as fouling behavior, was evaluated under different environmental conditions. The modified membrane formed an approximately 5 μm gel layer, showed reduced surface roughness, and increased pure-water flux by about 5.0%. It removed four antibiotics more effectively than the pristine membrane, with the greatest improvement for ofloxacin. Environmental conditions strongly affected antibiotic removal but had limited effects on ARG reduction. Low pH favored sulfamethoxazole, tetracycline, and ofloxacin removal, while 5 μm particles increased sulfamethoxazole and tetracycline removal by 27.0% and 22.0%, respectively. Hermia model fitting suggested predominantly standard blocking-type hydraulic behavior under the tested pH conditions and complete blocking-type behavior in the presence of HA or particles. These results show that PVA/TiO2 modification improves PES membrane hydrophilicity and antibiotic removal, although fouling under complex conditions remains important.