Synchronous Removal of Small-Sized Antibiotics by a Bifunctional Photocatalytic Nanofiltration Membrane in a Continuous Flow-Through Process under Multiple Influent Matrices

Bifunctional photocatalytic nanofiltration (PNF) membranes are of increasing significance in removing micropollutants in the actual water environment, but there are still critical bottlenecks that greatly limit their practicality. In this work, a metal-free and visible light-responsive surface-anchored PNF membrane was fabricated for simultaneously and efficiently removing target antibiotics from real river water in a continuous flow-through process. The results exhibited that the optimal PNF-3 membrane was expectedly consisted of an inside tight sub-nanopore structured separation layer and an outside thinner, super hydrophilic mesoporous degradation layer. Consequently, the PNF-3 membrane irradiated via visible light exhibited outstanding removal rates of sulfamethoxazole, trimethoprim, and chloramphenicol (between 99.0 and 99.9%), accompanied with almost constant high water permeability. In addition, after repeating the fouling–physical rinsing process three times that lasted for 60 h, only sporadic adherent contaminants remained on the top surface, together with minimal total and irreversible fouling ratios (only 7.9 and 1.2%), strongly proving that the PNF-3 membrane displayed good self-cleaning performance. In addition, the acute and chronic biotoxicities of its permeate to Virbrio qinghaiensis sp. -67 were also reduced significantly to 11.4 and 10.1%, respectively. This study might provide valuable insights into the continuous enhancement of the practicality and effectiveness of PNF membranes in micro-polluted water purification scenarios.