Cellulaose acetate based thin film nanocomposite reverse osmosis membrane incorporated with TiO2 nanoparticles for improved performance

In this work, cellulose acetate (CA) based thin film nanocomposite reverse osmosis (RO) membranes were fabricated using dissolution casting method by optimizing the CA/polyethylene glycol (CA/PEG-400) ratios for improved RO performance. The selectivity of optimized membrane was further enhanced by incorporating TiO2 (0-25 wt.%) nanoparticles. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were conducted to characterize control and modified membranes for the analysis of functional groups, thermal properties, morphology and structural investigation respectively. CP-2 of CA/PEG-400 (80/20) was selected for further modification with TiO2 nanoparticles. The maximum salt rejection (95.4%) was observed for the membrane having 15% TiO2 nanoparticles. Further escalation of TiO2 concentration resulted in the agglomeration of nanoparticles which subsequently decreased the permeation flux. The test results demonstrated that the modified membranes had higher salt rejection and chlorine resistance, lower degradation profile, successful inhibition of Escherichia coli growth and facilitating permeation flux compared to the control membrane.