Preparation and Characterization of PES-based Membranes : Impact of the Factors Using a Central Composite an Experimental Design

In this work, PES (polyethersulfone) /PVP (Polyvinylpyrrolidone) blend membranes and PES (Polyethersulfone) /ZnO (Zinc Oxide) mixed-matrix membranes (MMMs) were fabricated by a phase-inversion method. The membranes were characterized by several techniques including FTIR-ATR, porosity, water permeability and membrane performance in lysozyme solution (0.35 g/L). It was revealed that the casting speed influences the permeability of these membranes with variation rate of 67% for casting speed 20 and 30 mm/s. The porosity increases with the addition of PVP and ZnO nanopartticles (NPs). The porosity of PES/PVP membranes and PES/ZnO MMMs increased by 246% and 31% with respect to that of the PES membrane by adding PVP and ZnO NPs, respectively. Water flux of PES/ZnO hybrid membranes (with 0.5% of added ZnO NPs) significantly improved after the addition of ZnO NPs of 170%. The lysozyme rejection performance at 3 bar was found similar for the PES and PES/PVP membranes (85% and 86%, respectively) and slightly lower (75%) for the PES/ZnO hybrid membranes. The optimal permeability of 17.7 L.h-1.m-2.bar-1 was achieved with solvent and ZnO NPs percentages of 70% and 0.5%, respestively, and a casting speed of 20 mm/s.