Optimization of the synthesis of ultrafiltration asymmetric membranes based on organic polymers

Abstract

During this present study, we were able theoretically and experimentally to optimized the synthesis of permeable and asymmetric membranes (PSU-M1 and PSU-EPS-M2). These membranes are synthesized based on polysulfone polymer (PSU) as basic matrix, expanded polystyrene (EPS) recycled as additives, N, N′-dimethyl formamide (DMF) as a solvent and water as a non-solvent. The 2K factorial design method and the phase inversion technique allowed us to optimize the synthesized membranes. Membranes obtained were tested by measuring permeability flux, selectivity rate, thickness, swelling rate and mechanical resistance. Also, synthesized membranes were characterized using Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (NMR) spectroscopy and Scanning Electron Microscope (SEM). The experiment’s results are in good agreement with theoretical approaches that we envisaged. Further, we exploited the membranes realized in the ultrafiltration technique whose optimal conditions are 14%-PSU-M1 and 11-3%-PSU-EPS-M2. The present study has shown that the membranes chosen to initiate the theme of this research have a maximum permeability of the order 3030 ​L/m2.bar for the membrane 14%-PSU-M1 and of the order 2970 ​L/m2.bar for the membrane 11-3%-PSU-EPS-M2. These membranes have a selectivity rate of the percentage 90% with respect to the membrane 14%-PSU-M1 and of the percentage 93% relative to the membrane 11-3%-PSU-EPS-M2 at a threshold cutoff equivalent to 240 ​kDa of dextran, respectively. Keywords: Asymmetric membranes, Polysulfone polymer, Expanded polystyrene, Optimization, 14%-PSU-M1, 11-3%-PSU-EPS-M2, Selectivity rate