Fabrication and characterization of GO-TiO2 embedded PSF-PVP polymer composite membranes for enhanced membrane characteristics and antifouling performance

The effect of GO-TiO2 nanofiller (with TiO2 having a particle size not greater than 50 nm) on polysulfone (PSF) and polyvinylpyrrolidone (PVP) nanofiltration membranes fabricated by the phase inversion technique has been investigated in detail. The different weight ratios of hydrophilic nanofiller GO-TiO2, namely 0.25-0.75, 0.50-0.50 and 0.75-0.25 have been incorporated in the PSF-PVP matrix in order to enhance the membrane characteristics. PVP and GO-TiO2 composite were used as an additive and nanofiller in casting solution, acting as prominent pore former. Membranes were characterized to examine their properties such as hydrophilicity, thermal and mechanical stability. Particle size, distribution and morphology of the membranes has been analyzed by field emission scanning electron microscope (FESEM). Performance of the membrane and its antifouling properties due to the incorporation of this nanofiller have been investigated using contact angle, pure water flux, salt & hydrocarbon rejection and fouling resistance. It has been clearly observed that the incorporation of this nanofiller improved membranes' hydrophilicity which is the actual cause of membrane performance. Membrane, PSF-PVP/GO-TiO2 (0.50-0.50) showed the best result with a lower contact angle around 59 degrees with a pure water flux of 23.14 Lm(-2)h(-1). The salt and hydrocarbon rejection were evaluated as 97% for NaCl, 98% for Na2SO4 and 100% for hydrocarbons. A flux recovery of 76% and 72% have been observed for membrane, PSF-PVP/GO-TiO2 (0.50-0.50) after NaCl and Na2SO4 rejection, respectively. An enhancement in flux recovery ratio (FRR%) was also observed for the same when compared with the bare membrane. These findings reveal that the nanofiller is a promising modifier to enhance the membrane characteristics and performances.