Enhancing the Antifouling and Antibacterial Properties of Thin‐Film Composite Polyamide Membranes via Surface Immobilization of a <scp>PVP</scp> / <scp>AgINP</scp> Hybrid

ABSTRACT Fouling and bacterial contamination significantly limit the efficiency of thin‐film composite polyamide (TFC/PA) membranes in water treatment. To overcome this, a PVP/AgI hybrid layer was grafted onto commercial TFC/PA membranes to enhance their antifouling and antibacterial properties. Silver iodide nanoparticles (AgINPs) were first synthesized in situ in 7.0% PVP with an optimized KI/AgNO 3 ratio (5/1), yielding uniform nanoparticles (~62.5 nm). This surface modification significantly improved membrane hydrophilicity, as the water contact angle decreased from 54.63° (unmodified TFC/PA) to 46.05° after PVP grafting and further to 41.35° following AgINPs incorporation. Importantly, the modification did not compromise the polyamide layer's salt retention, with NaCl retention remaining stable (~93.0%–93.8%) across all membranes. During an 8‐h filtration test, the TFC/PA‐ g ‐AgINPs membrane exhibited superior antifouling performance, maintaining a high normalized flux ( J / J o of ~0.97) and achieving higher antifouling properties (MFR ~73.00% and FRR ~98.00%) compared to the unmodified membrane (68.93% and 92.26%, respectively). Furthermore, the TFC/PA‐ g ‐AgINPs membrane demonstrated potent antibacterial activity against both E. coli and S. aureus , presenting a simple and highly effective approach for developing durable water‐treatment membranes.