High flux asymmetric gas separation membranes of modified poly(ether ether ketone) prepared by the dry phase inversion technique

The membrane preparation conditions were optimized in order to reduce the skin thickness and increase the gas fluxes consequently. Low nonsolvent volatility was found to be more important than a high solvent hardness for obtaining a high void fraction and a thin dense skin. Thus, from PEEKWC solutions in chloroform, with butanol as the nonsolvent, membranes with a dense skin of about 1 μm were obtained, exhibiting a CO2/N2 selectivity and an O2/N2 selectivity of 33 and 6, respectively, comparable to typical commercial membranes, but at a slightly lower permeance (8.3 × 10−8 m3/(m2 h Pa) (3.1 GPU) for CO2 and 1.5 × 10−8 m3/(m2 h Pa) (0.56 GPU) for O2) than typical commercial membranes, like polyimide composites.