In this work, hydrophilic polyacrylamide (PAM)-grafted ZnO nanoparticles (ZnO-g-PAM NPs) were prepared and embedded into the polyamide (PA) rejection layer of a thin-film nanocomposite (TFN) membrane to improve the FO performance and perm-selectivity, and antifouling properties. ZnO-g-PAM nanofiller was prepared via atom transfer radical polymerization (ATRP) technique to enhance the nanoparticle hydrophilicity and high dispersibility in aqueous media. The obtained hybrid nanofiller participates in the advantageous of both ZnO and PAM brushes presents a uniform dispersion of ZnO in the PA structure of the ZnO-g-PAM-modified TFN membranes. To enhance the water flux and antifouling properties, different amounts (200, 400, and 600 ppm) of ZnO-g-PAM nanofiller was dispersed in the aqueous phase of the IP process. The effect of ZnO-g-PAM concentration on the hydrophilicity, morphology, and roughness of PA thin layer and FO performance (water flux, reverse salt flux, and membrane selectivity) of the TFN membranes were investigated. In addition, the antifouling tendency and intrinsic properties of the TFN membranes were evaluated in cross-section FO and dead-end RO systems, respectively. The effects of ZnO-g-PAM nanofiller on the IP process cause changes in surface morphology, thickness, and chemical composition of PA layer, improving the antifouling properties. As a results, the fabricated TFN-ZP₄₀₀ sample was confirmed to has an optimal water flux (20.5 LMH), compared to TFC (12.2 LMH) and other TFN membranes. Meanwhile, salt reverse flux (2.5 gMH) was maintained at a minimum level. Also, the high hydrophilicity of ZnO-g-PAM nanofiller in the PA structure leads to the hydration layer formation on the ZnO-g-PAM-modified PA layer, which minimize the fouling tendency. Therefore, the present study is the first time to consider the implementation of ZnO-g-PAM onto TFN-FO membranes.

Graphical Abstract