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This work presents a study on mixed matrix membranes (MMMs) of the polymer of intrinsic microporosity PIM-1, embedding the crystalline Cr-terephthalate metal-organic framework (MOF), known as MIL-101. Different kinds of MIL-101 were used: MIL-101 with an average particle size of ca. 0.2 µm, NanoMIL-101 (ca. 50 nm), ED-MIL-101 (MIL-101 functionalized with ethylene diamine) and NH 2 -MIL-101 (MIL-101 synthesized using 2aminoterephthalic acid instead of terephthalic acid). Permeability, diffusion and solubility coefficients and their corresponding ideal selectivities were determined for the gases He, H 2 , O 2 , N 2 , CH 4 and CO 2 on the "as-cast" samples and after alcohol treatment. The performance of the MMMs was evaluated in relation to the Maxwell model. The addition of NH 2 -MIL-101 and ED-MIL-101 does not increase the membrane performance for the CO 2 /N 2 and CO 2 /CH 4 separation because of an initial decrease in selectivity at low MOF content, whereas the O 2 and N 2 permeability both increase for NH 2 -MIL-101. In contrast, MIL-101 and NanoMIL-101 cause a strong shift to higher permeability in the Robeson diagrams for all gas pairs, especially for CO 2 , without significant change in selectivity. Unprecedented CO 2 permeabilities up to 35,600 Barrer were achieved, which are among the highest values reached with PIM-1 based mixed matrix membranes. For various gas pairs, the permeability and selectivity were far above the Robeson upper bound after alcohol treatment. Short to 21/11/2018 16.36.31 PIM-MIL-101 manuscript_SEPPUR_Final_revised_clean.docx p. 2/24 medium time aging shows that alcohol treated samples with MIL-101 maintain a systematically higher permeability in time. Mixed gas permeation experiments on an aged ascast sample with 47 vol% MIL-101 reveal that the MMM sample maintains an excellent combination of permeability and selectivity, far above the Robeson upper bound (CO 2 =3,500-3,800 Barrer, CO 2 /N 2 = 25-27; CO 2 /CH 4 =21 -24). This suggests good perspectives for these materials in thin film composite membranes for real applications.

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.

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