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

Abstract

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.