Antimicrobial Thin-Film Composite Polyamide Nanofiltration Membrane with High Desalination and Flux Performance Manufactured Through a Novel UV Light Driven Photoreduction Method That Generates Dispersed Silver Nanoparticles

Incorporation of antibacterial Ag nanoparticles (AgNPs) is thought to effectively control the biofouling of the thin-film composite (TFC) nanofiltration membrane for efficient desalination. In this study, a UV photoreduction reaction was employed for the first time to introduce AgNPs into the separation active layer of nanofiltration membrane to avoid the normal membrane blockage by conventional blending method. The additional merit of the UV irradiation was the partial oxidation of membrane surface, which provides more hydrophilic groups. Compared with the pristine TFC membrane, the AgNPs-loaded (TFC-Ag) membrane possessed much better hydrophilic property (with an increase in pure water flux by 99%), and maintained high salt rejection efficiency. The high antibacterial performance of the TFC-Ag membrane was demonstrated by the 96% inhibition efficiency to Escherichia coli. Besides, the TFC-Ag membrane only showed a trace amount of Ag+ release in the static and dynamic tests, showing great stability for water treatment. This study provides an innovative strategy for the in-situ production of metallic nanoparticles to modify the nanofiltration membrane and to improve its water flux and anti-bacterial performance.