Preparation and Characterization of Amine-functional SAPO-۳۴ Mixed Matrix Membranes for CO۲/CH۴ Separation

Removal of CO۲ in natural gas refining has currently been the only membrane based process practiced on a large scale operation. Despite the predominance of polymeric membranes in the CO۲/CH۴ separation, the tradeoff limitation in between membrane selectivity and permeability hinders a good separation performance of these membranes. Mixed matrix membranes can offer dramatic improvement to overcome this shortcoming. In this study, polyetheresulfone mixed matrix membranes incorporated with small pore amine modified SAPO-۳۴ were proposed for CO۲ separation. SAPO-۳۴ zeolite was used as inorganic fillers to enhance gas selectivity. The asymmetric membrane structure was prepared using the phase inversion method in order to improve permeance. SEM images and FTIR analysis were used to characterize the filler particles and the synthesized membranes. SEM images also indicated that, there were appropriate distribution particles in the polymer matrix.The effects of filler loading (۰-۱۰ wt%), feed temperature (۳۰۳-۳۴۳ K) and feed pressure (۰.۵-۴ bar) on CO۲/CH۴ selectivity of the MMMs were investigated. The results indicated that addition of amine-functional SAPO-۳۴ in the casting solution enhanced the membrane gas permeance and CO۲/CH۴ ideal selectivity. For the membrane with ۱۰ wt% of amine loading, selectivity was ۱۷% higher than the membrane without functionalizing with amine Increasing the temperature from ۳۰۳ to ۳۴۳ K reduced selectivity around ۲۵-۳۰.۵ %.