A Metal Chelating Porous Polymeric Support: The Missing Link for a Defect-free Metal-Organic Framework Composite Membrane

Abstract
Since the discovery of size-selective metal-organic frameworks (MOFs), researchers have tried to incorporate these materials into gas separation membranes. Impressive gas selectivities were found, but these MOF membranes were mostly made on inorganic supports, which are generally too bulky and expensive for industrial gas separation. Forming MOF layers on porous polymer supports is industrially attractive but technically challenging. Two features to overcome these problems are described: 1) a metal chelating support polymer to bind the MOF layer, and 2) control of MOF crystal growth by contra-diffusion, aiming at a very thin nanocrystalline MOF layer. Using a metal chelating polythiosemicarbazide (PTSC) support and adjusting the metal and organic ligand concentrations carefully, a very compact ZIF-8 (ZIF=zeolitic imidazolate framework) layer was produced that displayed interference colors because of its smooth surface and extreme thinness-within the range of visible light. High performances were measured in terms of hydrogen/propane (8350) and propylene/propane (150) selectivity.

Citation
Barankova E, Tan X, Villalobos LF, Litwiller E, Peinemann K-V (2017) A Metal Chelating Porous Polymeric Support: The Missing Link for a Defect-Free Metal-Organic Framework Composite Membrane. Angewandte Chemie International Edition 56: 2965–2968. Available: http://dx.doi.org/10.1002/anie.201611927.

Acknowledgements
The authors gratefully acknowledge financial support from King Abdullah University of Science and Technology (KAUST) and they thank Rahul Shevate for measuring the zinc binding capacity of PTSC.

Publisher
Wiley

Journal
Angewandte Chemie

DOI
10.1002/anie.201611927
10.1002/ange.201611927

Additional Links
http://onlinelibrary.wiley.com/doi/10.1002/anie.201611927/abstract

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