Synthesis and characterization of PSF/PES composite membranes for use in oily wastewater treatment

Abstract

Environmental sustainability requires development of environmentally benign and energy efficient technology for treatment and disposal of wastewater. Membrane technology has emerged as a highly viable method for water treatment throughout the years. However, their limited commercial application has prompted a lot of researchers to explore different approaches to modify the membranes to enhance their performance. Polymer blending is one of the modifying techniques currently being explored to develop materials with unique anticipated properties depending on the type of membrane needed. This technique has shown improvement in the quality of the membrane by enhancing the mechanical strength as well as the performance of the membrane. In this study, blended polysulfone (PSF) and polyethersulfone (PES) membranes were synthesized at different PSF:PES ratios (100%:0%, 0%:100%, 50%:50%, 80%:20%, 20%:80% and 25%:75%) using N-Methyl-2-pyrrolidone (NMP) as a solvent via the phase inversion method. The quality and integrity of the membranes were checked via Scanning electron microscopy (for morphology); Thermogravimetric analysis (for thermal stability), Atomic force microscopy (for surface nature) and nanotensile measurement for mechanical strength. The flux, % rejection and porosity as the performance criteria of membranes showed a massive improvement in majority of the blended membranes than in pure PES and PSF membranes. AFM images indicated lower roughness in the pure PSF membrane as compared to the blended membranes. The tensile strength only improved on the 25%:75% membrane while the elasticity increased with an increase in PES concentration in the blended membranes. These results demonstrate the diversity of blending polymeric membranes to modify specific properties for desired function and highlight the possibility of more commercial application.