Forward osmosis application of modified TiO2-polyamide thin film nanocomposite membranes

Recently, TiO2 nanoparticles have improved the surface properties and performance of membranes. However, the agglomeration of the nanoparticles remains as one of the major obstacles for generating the uniform surface. One of the best ways to improve dispersion of nanoparticles is the modification of nanoparticles. In this study, chemical modification of TiO2 was approached using APTES as silane coupling agent. The new thin film nanocomposite (TFN) membranes were synthesized by incorporation of different concentrations of modified TiO2 nanoparticles in aqueous solution of 1,3-Phenylendiamine (MPD) to enhance the forward osmosis (FO) performance of the membranes. The fabricated TFN membranes were characterized in terms of membranes structure, surface properties, separation properties, FO performance, and compared with common thin-film composite (TFC) membrane. The morphological studies showed that the incorporation of modified TiO2 significantly changed the surface properties of FO membranes. The TFN membranes exhibited high water permeability and acceptable salt rejection in all ranges of the modified TiO2 loading (0.01–0.1 wt./v%) in comparison to the TFC membrane. The most permeable membrane, TFN 0.1, had a water flux about 40 L/m2 h when the active layer facing feed solution. These TFN FO membranes significantly improved the performance of the FO membranes.