Efficient Calculation of Diffusion Limitations In Nanoporous Materials: A Tool for Identifying Materials for Kinetic Separations

Abstract for oral presentation AIChE 2011 Annual Meeting

Title: Efficient Calculation of Diffusion Limitations in Nanoporous Materials: A Tool for Identifying Materials for Kinetic Separations

Authors: Emmanuel Haldoupis, Sankar Nair, and David S. Sholl

Abstract:

The very large number of distinct structures that are known for metal-organic frameworks (MOFs) and related nanoporous materials presents both an opportunity and a challenge for identifying materials with useful properties for targeted applications. We show that efficient computational models can be used to evaluate large numbers of materials for kinetic separations of light gases based on finding materials with large differences between the diffusion coefficients of adsorbed gas species. We introduce a geometric approach that rapidly identifies the key features of a pore structure that control molecular diffusion, and couple this with efficient molecular modeling calculations that predict the adsorption and diffusion properties at infinite dilution for a range of spherical adsorbates. We demonstrate our approach for > 500 MOFs[1] and a library of > 250,000 hypothetical silica zeolites[2] that was generated previously by Deem and co-workers[3]. We show that these calculations provide a useful screening tool for considering large collections of nanocrystalline materials and choosing materials with particular promise for more detailed modeling.

2.  Haldoupis, E., S. Nair, and D.S. Sholl, Pore size analysis of >250 000 hypothetical zeolites. Physical chemistry chemical physics : PCCP, 2011. 13(11): p. 5053-60.

3.  Deem, M.W., et al., Computational Discovery of New Zeolite-Like Materials. The Journal of Physical Chemistry C, 2009. 113(51): p. 21353-21360.