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We report the fabrication of the first continuous zeolite-like metal-organic framework (ZMOF) thin-film membrane. A pure phase sod-ZMOF, sodalite topology, membrane was grown and supported on a porous alumina substrate using a solvothermal crystallization method. The absence of pinhole defects in the film was confirmed and supported by the occurrence of quantifiable time-lags, for all studied gases, during constant volume/variable pressure permeation tests. For both pure and mixed gas feeds, the sod-ZMOF-1 membrane exhibits favorable permeation selectivity toward carbon dioxide over relevant industrial gases such as H2, N2, and CH4, and it is mainly governed by favorable CO2 adsorption.

Nanoparticles of zeolitic imidazolate framework-7 (nZIF-7) were blended with poly(ether imide) (PEI) to fabricate a new mixed-matrix membrane (nZIF-7/PEI). nZIF-7 was chosen in order to demonstrate the power of postsynthetic modification (PSM) by linker exchange of benzimidazolate to benzotriazolate for tuning the permeability and selectivity properties of a resulting membrane (PSM-nZIF-7/PEI). These two new membranes were subjected to constant volume, variable pressure gas permeation measurements (H, N, O, CH, CO, CH, and CH), in which unique gas separation behavior was observed when compared to the pure PEI membrane. Specifically, the nZIF-7/PEI membrane exhibited the highest selectivities for CO/CH, CO/CH, and CO/CH gas pairs. Furthermore, PSM-nZIF-7/PEI membrane displayed the highest permeabilities, which resulted in H/CH, N/CH, and H/CO permselectivities that are remarkably well-positioned on the Robeson upper bound curves, thus, indicating its potential applicability for use in practical gas purifications.

Harvesting water vapor from desert, arid environments by metal-organic framework (MOF) based devices to deliver clean liquid water is critically dependent on environment and climate conditions. However, reported devices have yet been developed to adapt in real-time to such conditions during their operation, which severely limits water production efficiency and unnecessarily increases power consumption. Herein, we report and detail a mode of water harvesting operation, termed ‘adaptive water harvesting’, from which a MOF-based device is proven capable of adapting the adsorption and desorption phases of its water harvesting cycle to weather fluctuations throughout a given day, week, and month such that its water production efficiency is continuously optimized. In performance evaluation experiments in a desert, arid climate (17–32% relative humidity), the adaptive water harvesting device achieves a 169% increase in water production (3.5 LH2O kgMOF−1 d−1) when compared to the best-performing, reported active device (0.7–1.3 LH2O kgMOF−1 d−1 at 10–32% relative humidity), a lower power consumption (1.67–5.25 kWh LH2O−1), and saves time by requiring nearly 1.5 cycles less than a counterpart active device. Furthermore, the produced water meets the national drinking standards of a potential technology-adopting country.

This work demonstrates the confinement of porous metal–organic framework (HKUST-1) on the surface and walls of track-etched nanochannel in polyethylene terephthalate (np-PET) membrane using a liquid-phase epitaxy (LPE) technique. The composite membrane (HKUST-1/np-PET) exhibits defect-free MOF growth continuity, strong attachment of MOF to the support, and a high degree of flexibility. The high flexibility and the strong confinement of the MOF in composite membrane results from (i) the flexible np-PET support, (ii) coordination attachment between HKUST-1 and the support, and (iii) the growth of HKUST-1 crystal in nanoconfined geometries. The MOF has a preferred growth orientation with a window size of 3.5 Å, resulting in a clear cut-off of CO2 from natural gas and olefins. The experimental results and DFT calculations show that the restricted diffusion of gases only takes place through the nanoporous MOF confined in the np-PET substrate. This research thereby provides a new perspective to grow other porous MOFs in artificially prepared nanochannels for the realization of continuous, flexible, and defect-free membranes for various applications.

Zeolitic imidazolate framework‐302 (ZIF‐302) was incorporated within a polyimide (PI) matrix in order to develop a highly selective and permeable mixed‐matrix membrane (MMM) for gas separation processes. On the basis of varying fabrication procedures, two different MMMs were formed: a dense MMM (ZIF‐302/d‐PI) and a spongy, self‐consistent MMM (ZIF‐302/s‐PI). The spongy membrane was shown to have self‐consistent and disconnected pores with a reduction in overall membrane density. For ZIF‐302/d‐PI, a 1.2–1.5‐fold increase in the permeability of H2, O2, N2, CO2, and CH4 was observed when compared with the pure d‐PI membrane. For ZIF‐302/s‐PI, even better improvements (up to 19‐fold higher) in permeance were achieved with negligible effects on selectivity. The gas transport mechanism was then analyzed and showed a considerable enhancement of diffusion coefficients for ZIF‐302/s‐PI, while ideal gas pair selectivities for CO2/N2, H2/CH4, and H2/N2 were found to be 24.8, 42.3, and 62.6, respectively. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48513.

A new cross-linked porous polymer was synthesized and its performance in the capture of carbon dioxide from a ternary gas mixture was demonstrated, and properties retained for over 45 cycles. This report represents one of the top performing porous organic materials for carbon capture.

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