TiO₂/CDs modified thin-film nanocomposite polyamide membrane for simultaneous enhancement of antifouling and chlorine-resistance performance

In this study, a titanium dioxide/carbon dots (TiO₂/CDs) hydrophilic nanocomposite photocatalyst with different contents was embedded in the polyamide layer of reverse osmosis (RO) membrane via interfacial polymerization to increase desalination performance and antifouling properties. The modified membranes showed smoother surfaces with reduced contact angles, causing to improve membrane fouling resistance. TiO₂/CDs nanocomposite, due to its photocatalytic activity, showed more flux recovery ratio (FRR) after irradiation of UV light during the washing process. The FRR was enhanced from 94.4 to 97.1% for 0.01 wt% TiO₂/CDs RO membrane by UV irradiation. The hydrophilic functional groups with negative charge increased the desalination efficiency of the modified membranes (99.2% NaCl rejection for 0.01 wt% TiO₂/CDs membrane). The membrane containing 0.01 wt% TiO₂/CDs presented the highest pure water and NaCl solution flux of (59.6 and 54.6 L·m⁻²·h⁻¹) at 15 bar, respectively. In addition, the used nanoparticles improved the chlorine resistance of the membranes. As a result, TiO₂/CDs nanocomposite with little amounts could be applied as a suitable nanofiller to increase the permeability, antifouling properties, and chlorine resistance for RO membrane modification.