In-situ complexation of silver nanoparticle on thin film composite reverse osmosis membrane for improving desalination and anti-biofouling performance

The study on the state-of-art desalination membranes related to their fundamental structure, property and performance has been sparked by the demand for commercially attractive high-performance membranes. In this study, the surface of polyamide (PA) reverse osmosis (RO) membrane was modified by integrating tannic acid (TA) and silver nanoparticles (Ag NPs) to increase the water flux, anti-biofouling and antifouling properties of the membrane. The anti-biofouling properties was optimized by varying the duration required for the in-situ formation of Ag NPs on the surface grafted TA. The findings revealed that the PES/PA-TA-Ag(20 min) membrane prepared from the in-situ reduction of Ag precursor for 20 min exhibited the maximum flux of 20.56 L/m2·h. The PES/PA-TA-Ag(40 min) membrane also demonstrated increased antibacterial ability as proven by an increase in the number of dead bacteria (48 ± 1.71 μm3/μm2) and a reduction in biofilm thickness (1.6 ± 0.12 μm) for E. coli. The antifouling performance of the SA-fouled PES/PA-TA-Ag(40 min) membrane is appealing, with higher FRR of 98.05 % observed. The PES/PA-TA-Ag(40 min) membrane showed minimal silver leaching of ≤2.5 % and reduced flux loss of 25 % upon filtration. The facile surface modification through complexation of TA and Ag NPs offers an opportunity to heighten the desalination productivity and antifouling characteristics of PA TFC membranes.