Synthesis, Characterization and Gas Permeation study of CA/PEG/Zn-Co ZIF Mixed Matrix Membrane

Abstract

Exceptional permeabilities and perm-selectivities for CO2, N2, and CH4 have been reported using Zeolitic Imidazole Framework in polymeric mixed matrix membranes. This research focuses on synthesis, characterization and permeation testing of mixed matrix membrane using Zn-Co ZIF and Cellulose Acetate. Gases used are N2, CH4 and CO2. Zn-Co ZIF was synthesized using rapid room temperature method while mixed matrix membrane were synthesized using simple solution casting method. Excellent dispersion and morphology was obtained using Zn-Co ZIF and CA which was verified by various characterization techniques including SEM, X-ray Diffraction (XRD), FT-IR, Mechanical Testing using UTM and Thermo-gravimetric Analysis (TG). Characterization showed strong interaction between Zn-Co ZIF cages and cellulose acetate chains with excessive free volume elements for diffusion and excellent dispersion of Zn-Co ZIF on polymer surface. In permeability test system, pure CO2, N2, and CH4 were used and perm-selectivities were calculated for CO2/N2 and CO2/CH4 gas pairs. For CO2 maximum permeation of 160 barrer was obtained with 15wt% Zn-Co ZIF loading and 8 bar pressure. For N2, and CH4 maximum permeations of 6 and 5 barrer respectively were obtained. Perm-selectivity calculations showed very good results, for CO2/CH4 gas pair with 15wt% Zn-Co ZIF loading and 8 bar pressure was 26 which is very promising for industrial applications. For CO2/N2 gas pair, perm-selectivity was below industrially applicable value which might be enhanced by further modifications in composition. For this gas pair maximum perm-selectivity with 15wt% Zn-Co ZIF loading and 8 bar pressure was 32.