Metal-organic framework/graphene oxide composite fillers in mixed-matrix membranes for CO2 separation

Mixed-matrix membranes (MMMs) comprising of inorganic fillers dispersed in an organic matrix gather increased attention for separating gas mixtures due to potential for enhancement in separation selectivity, throughput, and material robustness. In the present study, ZIF-8 metal-organic framework (MOF) and ZIF-8/graphene oxide (GO) hybrid nanofillers were developed and incorporated into polysulfone (PSF) matrix. The fillers and the resulting MMMs were evaluated for their structural, morphological, and sorption characteristics, while the prepared membranes were tested for their permeation and selectivity properties for CO2, N-2 and CH4. It is highlighted that, compared to the pristine PSF membrane, the PSF+(ZIF-8/GO) MMMs showed both enhanced CO2 permeability (up to an increase of 87%), and selectivity (up to an increase of 61% for the CO2/CH4 pair). In addition, the selectivity for the PSF+(ZIF-8/GO) MMM was increased by up to 7-fold compared to that of the PSF ZIF-8 MMM. Based on the results reported, composite fillers combining the functionality of MOFs and GO have the potential to tune and boost the performance of polymeric membranes for CO2 separation from hydrocarbon gases, flue gas, and related gas mixtures. (C) 2018 Elsevier B.V. All rights reserved.