A new UiO-66-NH2 based mixed-matrix membranes with high CO2/CH4 separation performance.

Abstract A new UiO-66-NH 2 based MOF named UiO-66-NH 2 @ICA has been prepared by grafting imidazole-2-carbaldehyde (ICA) to UiO-66-NH 2 through a post-synthesis reaction via amine condensation. FESEM, XRD, 1H NMR, FT-IR and N 2 adsorption were used to characterize the morphology and structure of UiO-66-NH 2 @ICA. The grafted ICA mainly reduces the pore volume of UiO-66-NH 2 but increases the number of nitrogen atom as binding site of CO 2. The UiO-66-NH 2 @ICA showed less BET surface area but a higher CO 2 /CH 4 adsorption selectivity in comparison with UiO-66-NH 2. UiO-66-NH 2 @ICA and UiO-66-NH 2 crystals were dispersed in Matrimid®5218 to form mixed-matrix membranes (MMMs). Single gas permeation and mixed gas separation was carried out to investigate the effects of filler loading and feed gas pressure on the separation performances of the MMMs. The UiO-66-NH 2 @ICA/Matrimid® MMM with 10 wt % filler showed a high CO 2 /CH 4 selectivity with a separation factor of 64.7, which is an increase by 40% in comparison with UiO-66-NH 2 /Matrimid® MMM. Graphical abstract Image 1 Highlights • UiO-66-NH 2 @ICA was prepared by grafting imidazole-2-carbaldehyde (ICA) to UiO-66-NH 2. • Nitrogen atoms as CO 2 binding site increased after post-synthetic modification of UiO-66-NH 2. • UiO-66-NH 2 @ICA showed a higher CO 2 /CH 4 adsorption selectivity than UiO-66-NH 2. • UiO-66-NH 2 @ICA/Matrimid® MMMs displayed a high CO 2 /CH 4 separation selectivity. [ABSTRACT FROM AUTHOR]