Preparation and Characterization of Polyarylsulfone Based Membranes for Water Purification

Abstract

The membrane technology has gained prominence in water purification because of its energy efficiency. However, the lack of suitable membrane is a major technological hurdle in its acceptance as a primary tool for water purification. The polyarylsulfone based membranes are widely used due to its superior thermal and mechanical stability. However, its poor hydrophilicity and fouling nature have driven further research in this area. Therefore, the present work is an attempt to improve the performance of polyarylsulfone based membranes for water purification. In this research work, the polyarylsulfones such as polysulfone and polyphenylsulfone (PPSU) were used for the fabrication of novel membranes. The performance of membranes was improved by different modification techniques such as blending, chemical modifications, coating, or nanocompositing. The prepared membranes were characterized by analyzing their morphology, topography, surface hydrophilicity, water uptake capacity, and porosity. The membrane performance was further evaluated by the permeability, selectivity, and antifouling studies. The water purification capability of these membranes was studied by the rejection of heavy metal ions, salts, proteins, and dyes present in the aqueous feed. The ultrafiltration flat sheet membranes prepared using hydrophilic modifiers such as sulfonated PPSU, polyethylene glycol-1000, and glycine betaine showed good heavy metal rejection than their pristine counterparts. The studies on the bath composition on sPPSU based membranes also showed to affect the membrane morphology and porosity. The nanoparticles (NP) such as chitosan NPs (CNP), silverloaded CNPs, and MoO3 NPs were prepared and used as additives to fabricate nanocomposite hollow fiber membranes. These modified membranes showed better antifouling and anti-biofouling properties. The thin-film composite nanofiltration membranes were also prepared by incorporating glycine and L-glutamine as hydrophilic additives. The addition of these additives improved the water flux without compromising the salt rejection. Overall, the modified membranes exhibited an enhancement in the hydrophilicity which resulted in the superior antifouling property.