Pillared cloisite 15A as an enhancement filler in polysulfone mixed matrix membranes for CO2/N2 and O2/N2 gas separation

The Cloisite 15A (C-15A), an organically modified montmorillonite clay, was further modified with iron (Fe) pillars. Mixed matrix membranes (MMMs) were fabricated by incorporating Fe pillared Cloisite 15A (P-C15A) at different loading percentage of 0.1-1.5 wt% within the polysulfone (PSf) matrix. Fabricated membranes were characterized using thermal studies (TGA and DSC) and scanning electron microscopy (SEM). The morphological studies of fabricated MMMs confirmed that the P-C15A was well embedded through the PSf matrix. To investigate the effect of P-C15A incorporation, MMMs were tested for their gas permeation behavior using pure CO2, N-2, and O-2 gases. The gas permeation of MMMs was increased with the increase in loading percentage of P-C15A, whereas the gas selectivity was maintained at par to that of neat PSf membrane until it diminished at 1.5 wt% percentage of P-C15A causing mineral agglomeration. PSf/P-C15A (1 wt%) MMMs exhibited 232% and 274% increase in CO2 and O-2 gas permeability respectively, while showing minimal variation in the selectivity of O-2/N-2 and CO2/N-2 compared to that of neat PSf membrane. Furthermore, the gas separation performance of neat and P-C15A incorporated MMMs were compared with the Robeson upper bound. The PSf/P-C15A (1 wt%) MMM shown to have CO2 permeability of 18.01 barrer with the CO2/N-2 and O-2/N-2 gas pair selectivities of 4.95 and 18.34 respectively, which depicted closeness towards the Robeson upper bound.

Automated summary

By incorporating Fe pillared Cloisite 15A (P-C15A) within the polysulfone (PSf) matrix, mixed matrix membranes (MMMs) were fabricated to exhibit increased gas permeability for CO2 and O-2 while maintaining gas selectivity, approaching the Robeson upper bound.