Effect of β-alanine modified graphene oxide on separation properties of thin film nanocomposite membrane in water desalination

Abstract

This study explores the potential enhancement of graphene oxide (GO) as a nanomaterial for thin film nanocomposite (TFN) membranes through functionalization with β-Alanine (βA) amino acid. The GO nanosheets were crosslinked by the heterobifunctional molecules of βA using a facile one-step method. Several GO- and βA-GO-based TFN membranes were fabricated by varying the GO and βA-GO content of the polyamide (PA) selective layer, and their physicochemical, desalination performance, and antifouling properties were compared with those of the pristine PA-based TF composite membrane (TFC). TFN membranes showed a smoother surface morphology and a lower thickness than TFC while βA-GO-containing membranes exhibited a thinner thickness and smoother surface morphology. The best βA-GO-based TFN membrane, comprising 0.05 wt% βA-GO, exhibited an outstanding pure water flux of 22.65 L/m2h.at 7.5 bar and high Na2SO4 and NaCl rejection of 93.06% and 91%, respectively, which were significantly higher than those of the GO-based TFN membrane. GO- and βA-GO-containing TFN membranes showed more desirable antifouling properties, and the best βA-GO-based TFN membrane showed remarkably higher reversible fouling of 65% and flux recovery ratio of 87.6% due to its smoother surface morphology. Results revealed that the use of βA as a cross-linker allows the control of the d-spacing of GO nanosheets in aqueous media and enhances the rejection of the PA/βA-GO TFN membranes.