The Effect of Polyethersulfone Concentration on Flat and Hollow Fiber Membrane Performance

Abstract Flat and hollow fiber (HF) membranes are made in order to determine the effect of the polyethersulfone (PES) concentration in the precursor film-casting solution on resultant flat and hollow fiber membrane performance. The additive polyvinyl-pyrrolidone (PVP) is included in the film-casting solution to ensure that membranes can be made over wide variations in the PES polymer concentration. In general, membrane permeability decreases and solute separation ability increases as the PES concentration increases. However, for both flat and HF membranes, performance is strongly dependent on whether the PES concentration is above or below the critical value. Flux greatly decreases and solute-separation ability increases when the critical PES concentration is surpassed. Membrane performance is generally optimized when the PES concentration is at the critical value.