Zeolitic imidazolate framework-7 as an ultra-selective nanofilter for H2 purification: atomistic simulation study

Author: Hu Zhongqiao   Chen Yifei  

Publisher: Taylor & Francis Ltd

ISSN: 0892-7022

Source: Molecular Simulation, Vol.38, Iss.10, 2012-09, pp. : 830-837

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Abstract

An atomistic simulation study is reported for H2 purification from a gas mixture in zeolitic imidazolate framework-7 (ZIF-7) membrane. The gas mixture (with composition H2:CO2:CO:CH4:H2O = 74:15:5:5:1) mimics a typical effluent gas in syngas production. The simulation demonstrates that ZIF-7 membrane can act as an ultra-selective nanofilter only allowing H2 to permeate, as attributed to the molecular sieving effect of small apertures in ZIF-7. The flux and permeance of H2 increase with increasing pressure. At a given pressure, H2 flux exhibits an Arrhenius-type relation with temperature. With increasing pressure, the activation energy of H2 permeation decreases. H2 molecules in the membrane adopt a preferential orientation parallel to phenylimidazolate building blocks. This study confirms experimental observations that ZIF-7 is an interesting membrane material for H2 purification and provides atomistic insight into the purification mechanism in ZIF-7 membrane.

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