Search

Abstract: Ordered mesoporous silica spheres (MCM-41) were used as fillers in polyimide (Matrimid) based mixed-matrix membranes (MMMs). The filler particles were functionalized with sulfonic acid (–SO3H) groups to increase the separation performance of the membranes by increasing the CO2 solubility. The fast diffusion of gases through the mesoporous materials, accompanied by this increased interaction with CO2, resulted in the simultaneous increase of gas permeability and selectivity. The functionalized membranes showed up to 31% increase in CO2 permeability and 14% increase in CO2/CH4 selectivity. In order to study the stability of these newly developed MMMs, they were tested at different operating conditions (temperatures, mixed-gas feeds and CO2 feed concentration). [Copyright &y& Elsevier]

Abstract: Mixed matrix membranes (MMMs) can potentially improve the separation performance of traditional polymeric membranes while still maintaining their processing advantages and lower costs. In this work, MMMs composed of acrylate derivatized polysulfone and functionalized mesoporous MCM-41 were prepared by solution casting. The voids at the polymer-filler interface were removed by the introduction of covalent linkages between the modified polymer and the functionalized fillers. Gas permeation results and SEM images of the synthesized MMMs confirmed a good adhesion and dispersion of the fillers within the polymer matrix. In comparison to MMMs with unmodified MCM-41, covalently linked MCM-41 fillers rendered the MMMs significantly higher CO2/CH4 and CO2/N2 selectivities due to the presence of a covalent link between the –NH2 group of the filler and the acrylate of the polymer. The highest ideal selectivities obtained here for CO2/N2 and CO2/CH4 were 32.97 and 31.48 (CO2 permeability=9.13Barrer), respectively. Different operating temperatures were also studied and activation energies calculated. [Copyright &y& Elsevier]

Abstract: This paper describes the performance of sulfonated aromatic poly(ether ether ketone) (S-PEEK) membranes, directly prepared from the sulfonated monomer, for CO2 separation from gas mixtures containing N2 or CH4. Dense membranes with different degrees of sulfonation were prepared via solvent evaporation. Increasing degree of sulfonation simultaneously improves the permeability and selectivity of both gas pairs. The effect of counterions was investigated by converting S-PEEK membranes from the Na+-form in which they are prepared, to the H+ and multivalent cationic forms. Gas permeability and selectivity for polymers with divalent and trivalent counterions were higher than those for polymers in the monovalent and H+-forms. In order to study the stability and potential industrial application of these membranes, they were tested at different conditions of feed pressure, temperature and CO2 feed concentration. [Copyright &y& Elsevier]