Gas permeation and selectivity of polysulfone/carbon non-woven fabric membranes with sponge and finger-like structures

Abstract

This research aims to investigate the effect of supporting polysulfone (PSF) membranes with different pore structures (sponge “SP” and finger “FP”) by non-woven carbon fibers (CF) on their gas permeability and selectivity for different gas mixtures (H2/CO2, H2/N2, and H2/CH4) to avoid the lower mechanical strength of the commercial membranes. The thickness of the PSF layer was modified during the preparation process using a phase inversion approach. The impact of the support CF fabric and different pore structures on the mechanical, chemical, thermal, permeability, and selectivity characteristics of the fabricated membranes were examined. The results revealed a strong incorporation between PSF and the fabric, resulting in enhanced pores, increased porosity and higher roughness. The FP membrane’s structure was found to have a smaller pore size of 56 nm, higher porosity (73.6%), surface roughness (44 nm) and higher strength (15.7 MPa) but less thermal stability (−36%) compared to the SP structure. Moreover, the SP structure exhibited higher gas permeability, particularly for H2, with improvements of 32% for H2 and CO2, 25% for CH4, and 10% for N2. Furthermore, the PSF/CF membrane with SP structure exhibited higher selectively with 15.8%, 26.9%, and 14.4% improvements for H2/CO2, H2/N2, H2/CH4, respectively, compared to FP membranes. These results suggest that CF fabric has great potential as a membrane substrate and PSF/CF membranes with SP structures have high potential for use in the H2 gas separation process in harsh environments.