(292f) Polycrystalline MOF Membranes on Hollow Fibers: Processing, High-Performance Separations, and Tunable Molecular Sieving

This talk will describe our recent progress^1-6 in the fabrication and properties of ZIF-type MOF molecular sieving membranes on polymeric and other hollow fiber platforms.

Membrane separation is a key component of strategies targeting step changes (rather than incremental ones) in cost and energy-efficiency during production of fuels and chemicals from conventional and renewable feedstocks. Two important barriers to the development of MOF membrane separation technology are (i) the difficulty in obtaining tunable, high-performance, and robust molecular sieving materials; and (ii) the lack of low-cost, scalable membrane fabrication processes.

A ‘multiscale’ approach to nanoporous membrane fabrication processing is required to successfully exploit their fundamentally attractive characteristics. We will discuss how ZIF-type MOF materials can be processed into polycrystalline membranes on hollow fiber platforms, with control over nanometer-scale defects as well as micron-scale transport and film crystallization phenomena within the hollow fibers. These membranes allow high-performance separations of molecules such as hydrogen, olefins, and isomers. The talk will conclude with examples of generalizing the above strategy towards a versatile MOF membrane technology that addresses a wider range of molecular separation targets.

Overall, this talk highlights the fact that crystalline nanoporous materials and membranes with precise molecular sieving characteristics can overcome limitations associated with ‘conventional’ polymeric, carbon molecular sieve (CMS), or hybrid/mixed matrix membranes. At the same time, the above ‘conventional’ materials and concepts can still be useful in the development of advanced nanoporous membranes. Fruitful insights of this nature – obtained during collaborations of the Nair group and the Koros group – are highlighted at various junctures of this talk.

1. K. Eum, C. Ma et al, Adv. Mater. Interfaces, 2017 (in press).

2. K. Eum et al, ACS Appl. Mater. & Interfaces, 8 (38), 25337-25342 (2016).

3. K. Eum et al, Adv. Funct. Mater., 26 (28), 5011-5018 (2016).

4. K. Eum, K. C. Jayachandrababu, F. Rashidi, K. Zhang et al, J. Am. Chem. Soc., 137, p. 4191-4197 (2015).

5. A. J. Brown et al, Science, 345 (6192), 72-75 (2014).

6. A. J. Brown et al, Angew. Chem. Intl. Ed., 124, p. 10767-10770 (2012).