Preparation and characterization of polyethersulfone membranes with p-toluenesulfonic acid and polyvinylpyrrolidone additives

Asymmetric polyethersulfone (PES) microfiltration flat sheet membranes were made by the phase inversion method (PIM). Different PES/polyvinylpyrrolidone (PVP)/p-toluenesulfonic acid (TSA)/N,N-dimethylformamide (DMF) ratios of casting solution were used. Pore size and air flow rate of membranes were measured by a microflow porometer. Using low operating pressure (0.5 kgf/cm2), pure water flux was measured. In this study, we obtained the results that show the concentration of TSA affect mean flow pore size and pore size distribution. In general, increase of the PES concentration in solution decrease water flux. However, in our experiment, the water flux increased although the PES concentration increased. This would result from combined effect of TSA and PVP addition to casting solution. However, the different concentration of TSA in casting solution did not affect considerably the air permeability, bubble point and surface pore size of the membrane as can be observed from FE-SEM and microflow porometer.