Large-scale computational screening of metal-organic frameworks for CH4/H2 separation

Molecular simulations were performed to study a diverse collection of 105 metal-organic frameworks (MOFs) for their ability to remove CH4 from CH4/H2 mixture. To investigate the practical industrial application in a pressure swing adsorption (PSA) process, working capacity was also considered in addition to selectivity. The results show that MOFs are promising candidate for this separation, which give higher adsorption selectivity with similar working capacity and higher working capacity with similar selectivity than the traditional nanoporous materials such as carbonaceous materials and zeolites. To quantitatively describe the structureproperty relationship for CH4/H2 mixture separation in MOFs, a new concept named adsorbility was defined, which shows strong correlation with limiting selectivity, with a correlation coefficient (r2) of 0.86. This work shows that although MOFs are promising materials for CH4/H2 mixture separation, more investigations that consider both selectivity and working capacity are necessary to screen MOFs in practical PSA application. (C) 2011 American Institute of Chemical Engineers AIChE J, 2012