Novel thin-film nanocomposite (TFN) membrane embedded with biomodal silica nanoparticles for water purification

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Modern reverse osmosis (RO)/nanofiltration (NF) membranes are primarily made of thin-film composites (TFC) fabricated through interfacial polymerization of mphenylene diamine (MPD) and organic trimesoyl chloride (TMC) on polysulfone (PSF) supporting membrane. In this study, two types of bimodal silica nanoparticles (~80 nm) with different internal pore structures were synthesized and incorporated into the polyamide (PA) thin-film layer during interfacial polymerization at concentrations varying from 0 to 0.1 wt%. The as-prepared membranes were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy, and their performances were evaluated in terms of the water permeability and salt rejection. The results showed the water permeability increased with increasing Bimodal Silica Nanoparticles (BSNs concentrations, reaching a maximum of 53.5 L/m2h at a BSNs concentration of 0.5 wt%. This represented a flux increase of approximately 40%, while a near constant salt rejection of 95% was maintained. The study demonstrated that the internal micro-mesoporous structures of bimodal silica nanoparticles contributed significantly to the membrane performance, which is consistent with previous studies with relatively uniform internal pores