Synthesis and Characterization of Some Hydrophilic Polysulfone Based Membranes and their Application for Sustainable Water Purification

Abstract

The intensifying obligation to clean, freshwater and declining obtainability from natural resources, water need to be conserved effectually to come across future requirements. This deteriorating condition fascinated the attention of global researchers towards nonconventional sources, such as ocean water, treated water and groundwater. Membrane separation processes have been established briskly in the past decade into the leading technology for effective water treatment. Among the commercially available polymeric membranes, polysulfone based membranes play an important role as it exhibits improved chemical, thermal and mechanical stability. However, the trade-off between permeability and solute rejection, reduced surface hydrophilicity and higher propensity towards fouling of polysulfone membranes urge further development. In this research work, polysulfone membrane performance was improved by incorporating hydrophilic polymeric nanoparticles and blending with hydrophilic polymers. The as-prepared composite or nanocomposite membranes were thoroughly characterized using analytical techniques. The nanocomposite hollow fiber ultrafiltration membranes were prepared with surface modified halloysite nanotubes, zwitterionic polymer nanoparticles and zwitterionically modified Fe3O4 demonstrated improved antifouling ability and dye rejection with higher permeability compared to the pristine membrane. The as-added nanoparticles not only increased the membrane surface porosity but also altered the surface hydrophilicity and charge. The polysulfone blend ultrafiltration membrane was fabricated, which exhibited enhanced heavy metal ions such as Pb2+ (91.5 %) and Cd2+ (72.3 %) rejection. To further improve the heavy metal rejection, thin-film composite/nanocomposite membranes were prepared. The as-prepared nanofiltration membranes demonstrated higher rejection of heavy metal ions such as Pb2+ (>98%) and Cd2+ (>95 %) and improved antifouling property.