Simultaneous increase in CO₂ permeability and selectivity by BIT-72 and modified BIT-72 based mixed matrix membranes

Gas separation membranes are a key development in eradication of harmful greenhouse gases such as carbon dioxide (CO₂). Different strategies have been utilized to enhance membrane performance and to overcome their drawbacks. In this study a unique approach has been utilized to enhance membrane performance. Initially mixed matrix membranes (MMM) were fabricated with a novel metal-organic framework (MOF), namely BIT-72 incorporated in Pebax®1657 matrix. At 30% loading of BIT-72, CO₂/CH₄ and CO₂/N₂ selectivities of 30.96 and 56.28 were achieved respectively with CO₂ permeability of 139 Barrer. To further enhance the performance of the MMM, BIT-72 was treated with plasma of N₂ or O₂ gases to prepare MMMs with same polymer (N₂-BIT-72 MMM and O₂-BIT-72 MMM, respectively). As a result, CO₂/CH₄ and CO₂/N₂ selectivity was enhanced to 43.07 and 72.64 respectively for N₂ plasma treated BIT-72 MMM (CO₂ permeability 146 Barrer) and for O₂ plasma treated BIT-72 MMM (CO₂ permeability 145 Barrer) CO₂/CH₄ and CO₂/N₂ selectivity was increased to 37.28 and 66.21 respectively. Plasma modified BIT-72 MMM showed promising results for further applications.