Synthesis of novel thin film nanocomposite (TFN) forward osmosis membranes using functionalized multi-walled carbon nanotubes

Novel thin-film nanocomposite (TFN) membranes were synthesized by interfacial polymerization for the forward osmosis (FO) application. Amine functionalized multi-walled carbon nanotubes (F-MWCNTs) were used as additive in aqueous solution of 1,3-phenylendiamine (MPD) to enhance the FO membranes performance. Different concentrations of F-MWCNTs (0.01, 0.05 and 0.1 wt%) were added to the aqueous solution. The fabricated TFN membranes were characterized in terms of membranes structure and surface properties, separation properties and as well as FO performance and subsequently compared with traditional thin-film composite (TFC) membrane. The surface hydrophilicity of TFN membranes was improved with increasing F-MWCNTs concentration in the aqueous solution. The morphological studies showed that the incorporation of F-MWCNTs significantly changed the surface properties of modified membranes. The FO performance was evaluated using 10 mM NaCl solution as feed solution along with 2 M NaCl solution as draw solution in both orientations. The TFN membranes exhibited high water permeability and acceptable salt rejection in the range of 0.01–0.1 wt% F-MWCNTs loading in comparison with TFC membrane. The most permeable TFN had a water flux (95.7 L/m2 h) nearly 160% higher than TFC membrane, which represents an excellent improvement in FO membranes.