Antibacterial performance of a novel Ag/PDA-coated PTFE membrane in photothermal air-gap membrane distillation system for upgrading hospital effluent quality with water flux enhancement

The increasing occurrence of antibiotic-resistant bacteria (ARB) in hospital wastewater poses serious environmental and public-health risks, requiring effective treatment solutions. This study evaluates the novel polydopamine-silver nanoparticles (Ag/PDA)-coated PTFE membrane in the photothermal air-gap membrane distillation for upgrading the hospital effluent quality, focusing on their antimicrobial and photothermal performance. Under solar-simulated light, the Ag/PDA membranes showed enhanced photothermal conversion, increasing feed temperature and improving vapor flux by 48.5% over the unmodified membrane (0.97 kg/m²·h). Antibacterial effectiveness against E. coli and S. aureus demonstrated strong inhibition, particularly with higher Ag loading. The membrane also achieved >99% rejection and showed high potential to reduce ARB in the distillate. Overall, the Ag/PDA-modified membranes provide dual functionality efficient MD performance and antimicrobial activity supporting their application in upgrading the hospital effluent quality with higher yield of water flux. • A new modified PTFE membrane with polydopamine-silver nanoparticle was developed. • The novel membrane is used in photothermal air-gap membrane distillation (AGMD) process. • The AGMD with the novel membrane enhanced antimicrobial and photothermal performance. • The AGMD system exhibited strong antibacterial activity against E. coli and S. aureus . • High rejection (>99%) of antibiotic-resistant bacteria in hospital effluent could be achieved.