Fabrication of Externally Skinned Polyetherimide Hollow Fiber Membranes for Gas Separation and their Membrane Structures

摘要

Using polyetherimide (PEI) as a membrane material, and N-methyl-2-pyrrolidone (NMP) as a solvent, asymmetric hollow fiber membranes for gas separations were prepared by dry/wet phase separation. Effects of bore fluid composites and heat post-treatment on membrane performance and separation properties of O_2/N_2, He/N_2 and H_2/N_2 were investigated. Using NMP/ H_2O as bore fluid solutions, the selectivity of O_2/N_2, He/N_2 and H_2/N_2 of PEI hollow fiber membrane were 4.22, 83.9 and 165, respectively, while the permeation fluxes of O_2, He and H_2 were 3.25 GPU, 64.6 GPU and 127 GPU, respectively. After Membrane no.3 was treated for one hour at the temperature of 50℃, the selectivity of O_2/N_2, He/N_2 and H_2/N_2 of PEI hollow fiber membrane were 7.57, 304 and 512, respectively, and the permeation fluxes of O_2, He and H_2 were 0.83 GPU, 33.4 GPU and 56.3 GPU, respectively. On the basis of Scanning Electron Microscope (SEM), membrane structures and phase inversion in the preparation of asymmetric PEI hollow fiber membrane were analyzed. Besides, the mechanical properties of asymmetric PEI hollow fiber membranes were discussed.