Sod-ZMOF/Matrimid® mixed matrix membranes for CO2 separation

Abstract

In this study, sod-ZMOF (zeolite-like metal organic framework with sodalite topology) crystals were synthesized in order to prepare polymer/sod-ZMOF mixed matrix membranes (MMMs) for CO2/CH4 separation. The sod-ZMOF crystals were then incorporated into Matrimid® polyimide matrix to form dense MMMs by a solvent-casting method. After the analyses of structural and thermal characteristics of the prepared membranes, their CO2/CH4 separation performances were determined by measuring single and mixed gas permeabilities with a constant volume–variable pressure method at steady-state. SEM images of the MMMs showed that ZMOF particles were dispersed homogeneously in the polymer matrix and there were no significant voids or defects at the filler/polymer interface. While single gas permeability measurements of the membranes showed that CH4 and CO2 permeability increased without any significant change in the ideal selectivity, binary gas permeability measurements indicated that both CO2 permeability and selectivity were enhanced, with the increasing amount of incorporated MOF indicating strong adsorption selectivity of sod-ZMOF for CO2.