Effect of polymer concentration on the structure and performance of polyetherimide hollow fiber membranes

In this paper, polyetherimide (PEI) hollow fiber membranes were used in gas–liquid contacting process. Porous polyetherimide hollow fiber membranes were fabricated via wet phase inversion method. The polymer concentration in dope solution varied from 10 to 15 wt%. Water was used as internal and external coagulant. Gas permeation test using helium as test gas, liquid entry pressure of water (LEPw) test and scanning electron microscopy (SEM) were used for membrane characterization. The mean pore size, effective surface porosity and void fraction of membranes decreased as the polymer concentration increased, while LEPw and membrane density increased. CO2 absorption rate of fabricated membranes were measured in a gas–liquid hollow fiber membrane contactor system using distilled water as absorbent and the results showed that CO2 absorption rate of membranes increases as polymer concentration decreases. In addition, CO2 absorption rate of hollow fiber membranes in which polyetherimide concentration was between 10 and 12 wt%, was higher than commercial PVDF hollow fiber membranes.