, Volume 24, Issue 3, pp 233–241 | Cite as

On the use of the IAST method for gas separation studies in porous materials with gate-opening behavior

  • Guillaume Fraux
  • Anne Boutin
  • Alain H. Fuchs
  • François-Xavier CoudertEmail author


Highly flexible nanoporous materials, exhibiting for instance gate opening or breathing behavior, are often presented as candidates for separation processes due to their supposed high adsorption selectivity. But this view, based on “classical” considerations of rigid materials and the use of the Ideal Adsorbed Solution Theory (IAST), does not necessarily hold in the presence of framework deformations. Here, we revisit some results from the published literature and show how proper inclusion of framework flexibility in the osmotic thermodynamic ensemble drastically changes the conclusions, in contrast to what intuition and standard IAST would yield. In all cases, the IAST method does not reproduce the gate-opening behavior in the adsorption of mixtures, and may overestimates the selectivity by up to two orders of magnitude.


IAST OFAST Co-adsorption Selectivity Metal–organic frameworks Flexibility 

Supplementary material

10450_2018_9942_MOESM1_ESM.pdf (369 kb)
Supplementary material 1 (PDF 370 KB)


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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Chimie ParisTech, PSL Research University, CNRS, Institut de recherche de Chimie ParisParisFrance
  2. 2.École Normale Supérieure, PSL Research University, Département de Chimie, Sorbonne Universités – UPMC Univ. Paris 06ParisFrance

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