Mixed Matrix Membranes Using SAPO-34/APMDES/PES for Carbon Dioxide/Methane Separation

Among various CO2-mitigation technologies, membrane-based technology has offered a more energy-efficient and eco-friendly process for CO2 separation from large emission sources Despite the predominance of polymeric membranes in the CO2/CH4 separation, the tradeoff limitation between membrane selectivity and permeability hinders a good separation performance of these membranes Mixed matrix membranes can offer a dramatic improvement to overcome this shortcoming In this study, polyethersulfone (PES) mixed matrix membranes incorporated with small pore zeolite were proposed for CO2/CH4 separation SAPO-34 zeolite was used as inorganic fillers to enhance gas selectivity 3 3- aminopropylmethyldiethoxysilane (APMDES) was proposed to modify SAPO-34 zeolite before adding into asymmetric PES MMMs. The mixed matrix membranes were then characterized by FTIR, TGA, SEM, and gas permeation analysis. The separation results revealed that the increment of temperature from 30 °C to 50 °C reduced the CO2/CH4 separation factor while increasing feed pressure from 3 bar to 15 and the increment of CO2 feed composition from 15 to 42.5 vol% increased the separation factor of PES/SAPO-34/APMDES. The DoE results showed that the feed pressure was the most significant process parameter that intensely affected the CH4 permeance, CO2 permeance, and CO2/CH4 separation factor. The synthesized MMMs in this study showed competitive CO2/CH4 separation performance compared with reported state-of-the-art PES-based membranes in pure gas permeation tests.