The effect of SiO2 nanoparticles on morphology and performance of thin film composite membranes for forward osmosis application

This paper presents polyamide nano-composite membrane containing silica nanoparticles (TFN) synthesized via in situ interfacial polymerization for the forward osmosis (FO) application. Different concentrations of silica nanoparticles (0.01, 0.05 and 0.1% w/v) were added to the aqueous solution as additive to improve the FO membrane performance. The prepared membranes were characterized by ATR-FTIR, SEM, AFM and hydrophilicity measurement. The structure of nanocomposite layer synthesized by interfacial polymerization was characterized by FTIR spectroscopy. The FTIR peaks confirmed the presence of polyamide layer with SiO2 nanoparticles. The morphological studies showed that the SiO2 nanoparticles were effectively attached to the FO membrane surface. The contact angle measurements showed that the hydrophilicity of FO membranes was improved with increasing SiO2 in the aqueous solution. The FO performance was measured using 10 mM NaCl solution as feed solution and 2 M NaCl solution as draw solution in both orientations. The TFN membranes showed higher water permeability and better salt rejection in the range of 0.01-0.1 wt.% silica loading in comparison with the TFC membrane. The water flux of the TFN membrane reached to a maximum of 36 +/- 2 L/m(2) h which is nearly 2 times as high as that of the TFC membrane and it was found that the membrane modified with 0.05 w/v.% silica nanoparticles showed the highest salt rejection (90 +/- 3%). (C) 2014 Elsevier B.V. All rights reserved.