Mixed Matrix Membranes Comprising of Polysulfone and Microporous Bio-Mof-1: Preparation and Gas Separation Properties

Abstract

MMMs ?? with permeable and selective filler materials have a potential to improve the polymeric membranes performance for gas separation. For the very first time, a Bio-MOF nature? was used as filler in MMMs. Bio-MOF-1 crystals showed well defined rectangular shapes (nano-bars) with lengths of 0.5-4.0 µm and width of 0.05-0.20 µm and smooth surfaces. SEM? images of membranes demonstrate good dispersion and interaction of the filler in the polymer matrix, even at high loadings. The gas transport properties of MMMs with Bio-MOF-1 loading up to 30 wt% were investigated, and the results revealed that the overall separation performance is increased by adding the filler and further increased with the filler loadings via increased in the CO2 diffusion and solubility resulting from the porous nature of the Bio-MOF-1 that offered an easy passage for the gas transportation, and due to the adsorption of CO2 in the polar amino functional groups in the pores of Bio-MOF-1. The CO2 permeability of synthesized MMMs was enhanced by 168% and ideal selectivity by 53% and 58% for CO2/CH4 and CO2/N2, respectively at 30 wt% loading as compared to pure PSf. For gas mixtures with a 50:50 (CO2/CH4) and (CO2/N2) feed composition, CO2 permeability at 30 wt% loading increased by 128% and 129% combined with enhanced selectivity by 46.7% and 34.2%, respectively for CO2/CH4 and CO2/N2 gas mixtures in comparison to pure PSf. All synthesized MMMs were tested at different condition of CO2 feed concentration, various operating temperatures and their activation energies were also calculated. Finally, the comparison with relevant literature showed that even without any functionalization of Bio-MOF-1, it showed higher selectivity than amine functionalized MOFs and quite comparable permeability.