Mixed matrix membranes containing MOFs for ethylene/ethane separation Part A: Membrane preparation and characterization

Mixed matrix membranes (MMMs) containing three different metal organic frameworks (MOFs) (Cu3BTC2, FeBTC and MIL-53 (Al)) as filler in P84 were prepared and characterized in terms of ethylene/ethane separating ability. SEM, TGA and DSC suggest the absence of non-selective voids in the Cu3BTC2 and FeBTC MMMs. Gas permeation experiments confirmed this, and showed an increase in ethylene/ethane selectivity of 73% to a value of 7.1, while ethylene permeability remained constant at 17×10−18 mol m/(m2 s Pa) with addition of 20 wt% Cu3BTC2. Addition of 20 wt% FeBTC showed a reduced permeability, caused by the formation of a denser intermediate layer, and no significant change in selectivity. Addition of MIL-53 led to increased permeabilities and no change in selectivity, which is probably the result of the formation of non-selective voids or the absence of inherent selectivity of MIL-53.

Ethylene/ethane selectivity of native P84 and 20 wt% Cu3BTC2, FeBTC and MIL-53 MMMs at 5, 10 and 15 bar mixed gas feed pressure.Figure optionsDownload high-quality image (227 K)Download as PowerPoint slideHighlights
► Addition of Cu3BTC2 to P84 increases the ethylene/ethane selectivity.
► Addition of Cu3BTC2 to P84 does not increase the ethylene permeability.
► Addition of FeBTC to P84 decreases the permeability while the selectivity remains constant.
► Addition of MIL-53 increases the permeability while the selectivity remains constant.