A dual defense strategy for antibacterial and anti-biofouling nanofiltration membranes: Integrating kasugamycin-derived networks with in situ silver functionalization

Membrane biofouling remains a major obstacle to the long-term efficiency of nanofiltration (NF) processes in water treatment. In this study, a novel dual-mechanism antibacterial NF membrane was fabricated by integrating an antibiotic monomer and silver nanoparticles (Ag NPs). Kasugamycin, an environmentally compatible aminoglycoside antibiotic, was employed as a functional aqueous monomer to replace traditional amines. The hydrophilic polyester-amide separation layer was constructed via interfacial polymerization, simultaneously incorporating the antibacterial groups. Ag NPs were subsequently immobilized in situ onto the membrane surface through a polydopamine interlayer, constituting the dominant antibacterial component. The resulting Kas-TMC-PDA-Ag membrane exhibited a high Na 2 SO 4 rejection of 98.81% and a competitive permeance of approximately 15 L m −2  h −1 bar −1 . Owing to the dominant bactericidal action of Ag NPs via silver ion release and reactive oxygen species (ROS) generation, complemented by the auxiliary role of kasugamycin in disrupting bacterial protein synthesis, the membrane achieved 100% antibacterial efficiency against both E. coli and S. aureus , while effectively suppressing biofilm formation. Furthermore, it displayed superior biofouling resistance compared to a commercial NF270 membrane, as evidenced by a higher flux recovery ratio (FRR) after bacterial fouling, and maintained excellent dynamic antifouling performance during the filtration of complex lake water with a FRR of 89.1%. With low silver leaching, exceptional operational and chemical stability, this study provides a high-efficiency approach for fabricating biofouling-resistant NF membranes for advanced water treatment.