A comparative study on the structure of developed porous PVDF and PEI hollow fiber membrane contactors for CO2 absorption

The structure of polyvinylidene fluoride (PVDF) and polyetherimide (PEI) hollow fiber membranes was developed by formulation of the polymer solutions and regulating spinning parameters. The cloud point diagrams of polymer/solvent/non-solvent were obtained to investigate phase inversion behavior of the solutions. The prepared membranes were characterized in terms of morphology, overall porosity, gas permeation, collapsing pressure, wetting resistance and mass transfer resistance. The gas-liquid membrane contactor modules were prepared to study CO2 absorption performance of the membranes. The PEI and PVDF membranes presented finger-like and sponge-like structure, respectively. Both membranes showed good surface porosity due to enhancement of phase inversion by addition of glycerol to the spinning solutions. The PVDF membrane presented mean pore size of 0.09 mu m with low mass transfer resistance and high wetting resistance. At water velocity of 0.03 m/s, the PVDF membrane indicated CO2 flux of 1.5x10(-3) mol/m(2) s which was 35 % higher than the flux of the PEI membrane. Due to the improved structure of the membranes, a significantly high CO2 flux was obtained at the same operating condition compared to the reported membranes in the literature. The developed membranes can be used as promising alternatives for cost-effective gas-liquid membrane contactor systems.