High-throughput computational screening of 137953 metal–organic frameworks for membrane separation of a CO 2 /N 2 /CH 4 mixture

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2016, Vol.4 (41), p.15904-15912
• Main Authors: Qiao, Zhiwei, Peng, Chunwang, Zhou, Jian, Jiang, Jianwen
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/C6TA06262H

As an environmentally benign energy source, natural gas needs to be upgraded by separating impurities ( e.g. CO 2 and N 2 ) from CH 4 . In the current upgrading technology, CO 2 and N 2 are separated via multiple energy-intensive steps. Herein, we report a computational study to high-throughput screen 137953 metal–organic frameworks (MOFs) for a single-step membrane separation of a CO 2 /N 2 /CH 4 mixture. The screening strategy consists of four stages. First, the pore limiting diameters (PLDs) are calculated and 17257 MOFs with a PLD of 3–4 Å are selected. Second, the Henry's constants, diffusivities and permeabilities of CO 2 , N 2 , and CH 4 in the 17257 MOFs are estimated at 298 K and infinite dilution by Monte Carlo and molecular dynamics simulations. Their quantitative relationships with the PLD are established. Third, based on permselectivity versus permeability plots, 24 MOFs are prescreened for both CO 2 /CH 4 and N 2 /CH 4 separation. Finally, the adsorption, diffusion, and permeation of a three-component CO 2 /N 2 /CH 4 mixture are simulated in the 24 prescreened MOFs at 298 K and 10 bar, and the 5 best MOFs are identified for the membrane separation of CO 2 and N 2 from CH 4 . This computational study reveals that the PLD and a new structural parameter (the percentage of pore size distribution) are key factors governing diffusion and permeation, provides quantitative structure–property relationships from the bottom up and would facilitate the development of new membranes for the upgrading of natural gas.