Issue 82, 2017

Molecular simulations of MOF membranes for separation of ethane/ethene and ethane/methane mixtures

Abstract

Metal organic framework (MOF) membranes have been widely investigated for gas separation applications. Several MOFs have been recently examined for selective separation of C2H6. Considering the large number of available MOFs, it is not possible to fabricate and test the C2H6 separation performance of every single MOF membrane using purely experimental methods. In this study, we used molecular simulations to assess the membrane-based C2H6/C2H4 and C2H6/CH4 separation performances of 175 different MOF structures. This is the largest number of MOF membranes studied to date for C2H6 separation. We computed adsorption selectivity, diffusion selectivity, membrane selectivity and gas permeability of MOFs for C2H6/C2H4 and C2H6/CH4 mixtures. Our results show that a significant number of MOF membranes are C2H6 selective for C2H6/C2H4 separation in contrast to traditional nanoporous materials. Selectivity and permeability of MOF membranes were compared with other membrane materials, such as polymers, zeolites, and carbon molecular sieves. Several MOFs were identified to exceed the upper bound established for polymeric membranes and many MOF membranes exhibited higher gas permeabilities than zeolites and carbon molecular sieves. Examining the structure–performance relations of MOF membranes revealed that MOFs with cavity diameters between 6 and 9 Å, porosities lower than 0.50, and surface areas between 500–1000 m2 g−1 have high C2H6 selectivities. The results of this study will be useful to guide the experiments to the most promising MOF membranes for efficient separation of C2H6 and to accelerate the development of new MOFs with high C2H6 selectivities.

Graphical abstract: Molecular simulations of MOF membranes for separation of ethane/ethene and ethane/methane mixtures

Supplementary files

Article information

Article type
Paper
Submitted
19 Oct 2017
Accepted
03 Nov 2017
First published
10 Nov 2017
This article is Open Access
Creative Commons BY license

RSC Adv., 2017,7, 52283-52295

Molecular simulations of MOF membranes for separation of ethane/ethene and ethane/methane mixtures

C. Altintas and S. Keskin, RSC Adv., 2017, 7, 52283 DOI: 10.1039/C7RA11562H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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