Production of super selective polysulfone hollow fiber membranes for gas separation

Polysulfone gas separation hollow fiber membranes were manufactured using a dry/wet spinning process with forced convection in the dry gap. Hollow fib ers were produced using two different bore coagulants: one pure water and o ne with reduced water activity. An optimized multi-component dope was used which proved to be a shear-thinning power-law fluid. For each bore system, membranes were spun at low and high dope extrusion rates (DERs) correspondi ng to shear rates of around 4000 s(-1) and 10 000 s(-1), respectively, at t he outer spinneret wall. Plane polarized infrared spectroscopy was used to probe the membrane active layer. Pressure-normalized fluxes and selectiviti es were evaluated using purl carbon dioxide and methane. For the spinning c onditions used here, the combination of reduced water activity in the bore and high DER produced highly selective membranes. Some selectivities reache d about three times the recognized intrinsic value for the polymer. (C) 199 9 Elsevier Science Ltd. All rights reserved.