Abstract Air separation is one of the most challenging separations because of the very similar molecular dimensions of gas molecules. We used a high-throughput computational screening approach to identify the… Click to show full abstract
Abstract Air separation is one of the most challenging separations because of the very similar molecular dimensions of gas molecules. We used a high-throughput computational screening approach to identify the upper performance limits of metal organic framework (MOF) membranes and MOF/polymer mixed matrix membranes (MMMs) for O2/N2 separation. Gas permeabilities and selectivities were calculated for 5629 MOF membranes and 78,806 different types of MOF/polymer MMMs, which represent the largest number of MOF-based membranes studied to date for air separation. Our results showed that many MOF membranes exceed the upper bound established for polymer membranes due to their high permeabilities and/or selectivities. The maximum achievable O2 permeability and O2/N2 selectivity of MOF/polymer MMMs were computed as 2710.8 Barrer and 19.8, respectively. Results revealed that MOF/polymer MMMs can outperform MMMs composed of traditional fillers, such as zeolites, in terms of O2 permeability and O2/N2 selectivity. The impacts of purity of air mixture and the structural flexibility of MOFs on the gas separation performances of MMMs were also discussed. These results provide molecular-level insights into adsorption and diffusion behaviors of O2 and N2 in MOF membranes in addition to presenting structure-performance relations of MOFs that can lead to high-performance membranes and fillers for MMMs.
               
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