THE EFFECT OF POLYETHERSULFONE CONCENTRATION ON FLAT AND HOLLOW-FIBERMEMBRANE PERFORMANCE

Flat and hollow fiber (HF) membranes are made in order to determine th e effect of the polyethersulfone (PES) concentration in the precursor film-casting solution on resultant flat and hollow fiber membrane perf ormance. The additive polyvinyl-pyrrolidone (PVP) is included in the f ilm-casting solution to ensure that membranes can be made over wide va riations in the PES polymer concentration. In general, membrane permea bility decreases and solute separation ability increases as the PES co ncentration increases. However, for both flat and HF membranes, perfor mance is strongly dependent on whether the PES concentration is above or below the critical value. Flux greatly decreases and solute-separat ion ability increases when the critical PES concentration is surpassed . Membrane performance is generally optimized when the PES concentrati on is at the critical value.