Solvent influence on the textural properties and CO2/N2 separation performance of novel Pebax-1657/attapulgite mixed matrix membranes

Mixed matrix membranes (MMMs) have gained significant attention in CO2 separation. However, the symmetrical dispersion of inorganic filler nanoparticles during MMMs fabrication is still a crucial challenge. The present work investigates the outcome of N-Methyl-2-pyrrolidone (NMP) and N-N-Dimethyl-formamide (DMF) solvents on MMMs texture, perm-selectivity and nanoparticles dispersion. Scanning electron microscopy (SEM), Fourier-transform-infrared (FTIR) and X-Ray Diffraction (XRD) analyses were also performed for membrane characterization. The MMMs fabricated with NMP solvent showed competitive CO2 permeability (120.20 barrer) and CO2/N-2 selectivity (69.31) compared to the membranes prepared with DMF solvent. It has been indicated that the molar volume, boiling point and solubility parameters were significant factors in the solvent selection. Moreover, the effect of operating temperature on gas transport properties showed substantial impact in perm-selectivity, at 3 bar feed-pressure, with the temperature dropping from 40 degrees C to 0 degrees C, the CO2/N-2 gases selectivity increased from 69.31 to 105.50, equating to a 64.8% decrease in CO2 permeability.

Automated summary

The MMMs fabricated with NMP solvent showed competitive CO2 permeability and selectivity; the selection of solvent depends on factors such as molar volume, boiling point, and solubility parameters; operating temperature has a significant impact on gas transport properties, with a decrease in temperature resulting in increased selectivity for CO2/N-2 gases.