Polymer hollow fiber membranes for gas separation: A comparison between three commercial resins

Polymer hollow fibre membranes are becoming more and more used for gas separation. In this work, asymmetric hollow fibre membranes were prepared by a phase inversion technique with three commonly used commercial polymers: polyethersulfone (PES), polyetherimide (Ultem (R) 1000), and polyimides (Matrimid (R) 5218). The effect of spinning parameters (composition of the dope and bore solution, bore flow rate, air gap distance, temperature of the spinneret and coagulation bath, as well as take-up speed) on the membrane morphology and gas permeation properties was investigated. The membrane separation performances were characterized in terms of gas transport properties (permeance/selectivity) for different gases (H-2, CO2, O-2, N-2, CH4) to relate this information with their morphology studied by scanning electron microscopy (SEM). Furthermore, dense flat membranes from the same materials were prepared by solvent casting to investigate the relationships between the gas separation performance and membrane configuration (hollow fibers vs. compact flat membrane). Finally, a comparison between the apparent skin layer thickness from O-2 permeability/permeance and SEM image gave good agreement.