Towards High Performance Metal-Organic Framework-Microporous Polymer Mixed Matrix Membranes: Addressing Compatibility and Limiting Aging by Polymer Doping.

Membrane separation for gas purification is an energy-efficient and environment-friendly technology. However, the development of high performance membranes is still a great challenge. In principle, mixed matrix membranes (MMMs) have the potential to overcome current materials limitations, but in practice there is no straightforward method to match the properties of fillers and polymers (the main components of MMMs) in such a way that the final membrane performance reflects the high performance of the microporous filler and the processability of the continuous polymer phase.

Synthesis of ZIF-93/11 Hybrid Nanoparticles via Post-Synthetic Modification of ZIF-93 and Their Use for H /CO Separation.

The present work shows the synthesis of nano-sized hybrid zeolitic imidazolate frameworks (ZIFs) with the rho topology based on a mixture of the linkers benzimidazole (bIm) and 4-methyl-5-imidazolecarboxaldehyde (4-m-5-ica). The hybrid ZIF was obtained by post-synthetic modification of ZIF-93 in a bIm solution. The use of different solvents, MeOH and N,N-dimethylacetamide (DMAc), and reaction times led to differences in the quantity of bIm incorporated to the framework, from 7.

Influence of Filler Pore Structure and Polymer on the Performance of MOF-Based Mixed-Matrix Membranes for CO Capture.

To gain insight into the influence of metal-organic framework (MOF) fillers and polymers on membrane performance, eight different composites were studied by combining four MOFs and two polymers. MOF materials (NH -MIL-53(Al), MIL-69(Al), MIL-96(Al) and ZIF-94) with various chemical functionalities, topologies, and dimensionalities of porosity were employed as fillers, and two typical polymers with different permeability-selectivity properties (6FDA-DAM and Pebax) were selected as matrices. The best-performing MOF-polymer composites were prepared by loading 25 wt % of MIL-96(Al) as filler, which improved the permeability and selectivity of 6FDA-DAM to 32 and 10 %, while for Pebax they were enhanced to 25 and 18 %, respectively.

Investigation of zeolitic imidazolate frameworks using C and N solid-state NMR spectroscopy.

Zeolitic imidazolate frameworks (ZIFs) are a subclass of metal-organic frameworks (MOFs) with extended three-dimensional networks of transition metal nodes (bridged by rigid imidazolate linkers), with potential applications in gas storage and separation, sensing and controlled delivery of drug molecules. Here, we investigate the use of C and N solid-state NMR spectroscopy to characterise the local structure and disorder in a variety of single- and dual-linker ZIFs. In most cases, a combination of a basic knowledge of chemical shifts typically observed in solution-state NMR spectroscopy and the use of dipolar dephasing NMR experiments to reveal information about quaternary carbon species are combined to enable spectral assignment.