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Metal-organic frameworks (MOFs) were supported on polymer membrane substrates for the fabrication of composite polymer membranes based on unmodified and modified polymer of intrinsic microporosity (PIM-1). Layers of two different MOFs, zeolitic imidazolate framework-8 (ZIF-8) and Copper benzene tricarboxylate ((HKUST-1), were grown onto neat PIM-1, amide surface-modified PIM-1 and hexamethylenediamine (HMDA) -modified PIM-1. The surface-grown crystalline MOFs were characterized by a combination of several techniques, including powder X-ray diffraction, infrared spectroscopy and scanning electron microscopy to investigate the film morphology on the neat and modified PIM-1 membranes. The pure gas permeabilities of He, H2, O2, N2, CH4, CO2 were studied to understand the effect of the surface modification on the basic transport properties and evaluate the potential use of these membranes for industrially relevant gas separations. The pure gas transport was discussed in terms of permeability and selectivity, highlighting the effect of the MOF growth on the diffusion coefficients of the gas in the new composite polymer membranes. The results confirm that the growth of MOFs on polymer membranes can enhance the selectivity of the appropriately functionalized PIM-1, without a dramatic decrease of the permeability. [ABSTRACT FROM AUTHOR]

This work presents a study of the gas transport properties for a novel class of mixed matrix membranes (MMMs) based on the polymer of intrinsic microporosity PIM-1 loaded with UiO-66 [Zr 6 O 4 (OH) 4 (O 2 CC 6 H 4 CO 2 ) 6 ] based metal-organic frameworks (MOFs). Three isoreticular MOFs were dispersed in the polymer matrix, standard UiO-66, UiO-66-NH 2 (functionalized with an amino group) and UiO-66-(COOH) 2 (functionalized with two carboxylic groups), in order to investigate the effect of the functionalization of the linker on the gas transport. The pure gas permeabilities of He, H 2 , O 2 , N 2 , CH 4 , CO 2 were studied, for the as prepared membranes and after methanol treatment, focusing attention on the potential use of these membranes for CO 2 /CH 4 separation. The pure gas transport of the MMMs was described on the basis of the Maxwell model. The predictions of the model are discussed and compared with the experimental permeability and selectivity of the MMMs and neat PIM-1. Mixed gas permeation tests were performed on a representative sample to investigate the actual separation performance with industrially relevant gas mixtures. These confirmed the good perspectives of these MMMs in applications like CO 2 removal from biogas or from flue gas. [ABSTRACT FROM AUTHOR]