DEVELOPMENT OF A NOVEL GO-SIO2-PEI DOPED POLYSULFONE MEMBRANE FOR OIL-IN-WATER SEPARATION

Abstract

This thesis presents the development and optimization of novel polysulfone (PSF) membranes incorporated with GO-SiO2-PEI nanocomposites and polyvinylpyrrolidone (PVP) for effective oily-water separation. A systematic review of SiO2-polymer composite membranes highlighted significant advancements in membrane technology, particularly in enhancing hydrophilicity, permeability, and stability through the incorporation of nanocomposites. The review also identified challenges such as nanoparticle leaching and long-term stability, with a noted gap in using crossflow filtration setups to better simulate real operational conditions. The study successfully synthesized GO-SiO2-PEI nanocomposites through a series of functionalization steps, confirmed by Raman, XPS, XRD, and FTIR analyses. The incorporation of this nanocomposite into PSF membranes resulted in significant improvements in membrane morphology, permeability, and oil rejection. At 1.0 wt% nanocomposite loading, the membrane exhibited an 809% increase in water flux, a 57% improvement in flux recovery rate, and maintained a high oil rejection rate of 97.6%. The addition of nanocomposites increased the polar surface energy, leading to improved oil rejection and a reduction in fouling tendencies. Further optimization of the PSF/PVP/GO-SiO2-PEI membranes was achieved by incorporating PVP as a pore-forming agent, which enhanced membrane porosity, hydrophilicity, and surface roughness. Membranes with 5% PVP and 0.5% GO-SiO2-PEI demonstrated the highest oil rejection (87.3%), the best flux recovery ratio (94%), and the lowest fouling tendency (14%), with a significant reduction in surface roughness. Crossflow filtration tests confirmed the effectiveness of these membranes in simulating real-world operational conditions, revealing their potential for long-term use in oily-water separation. This research highlights the successful integration of GO-SiO2-PEI nanocomposites into PSF membranes for enhanced performance in oily wastewater treatment. The study provides valuable insights into membrane optimization, addressing key challenges such as fouling resistance and long-term stability, while suggesting directions for future work including nanoparticle dispersion optimization, scale-up studies, and the development of self-cleaning membranes for industrial applications.