The Influence of UiO-66 Metal–Organic Framework Structural Defects on Adsorption and Separation of Hexane Isomers

The Influence of UiO-66 Metal–Organic Framework Structural Defects on Adsorption and Separation of Hexane Isomers

Sławek, Andrzej (AGH University of Science and Technology)
Jajko, Gabriela (Jagiellonian University)
Ogorzały, Karolina (Jagiellonian University)
Dubbeldam, David (Universiteit van Amsterdam)
Vlugt, T.J.H. (TU Delft Engineering Thermodynamics)
Makowski, Wacław (Jagiellonian University)

2022

In this work, adsorption properties of the UiO-66 metal–organic framework were investigated, with particular emphasis on the influence of structural defects. A series of UiO-66 samples were synthesized and characterized using a wide range of experimental techniques. Type I adsorption isotherms for low-temperature adsorption of N₂ and Ar showed that micropore volume and specific surface area significantly increase with the number of defects. Adsorption of hexane isomers in UiO-66 was studied by means of quasi-equilibrated temperature-programmed desorption and adsorption (QE-TPDA) experimental and Monte Carlo simulation techniques. QE-TPDA profiles revealed that only defect-free UiO-66 exhibits distinct two adsorption states. This technique also yielded high-quality adsorption isobars that were successfully recreated using Grand-Canonical Monte Carlo molecular simulations, which, however, required refinement of the existing force fields. The calculations demonstrated the detailed mechanism of adsorption and separation of hexane isomers in the UiO-66 structure. The preferred tetrahedral cages provide suitable voids for bulky molecules, which is the reason for unusual “reverse” selectivity of UiO-66 towards di-branched alkanes. Interconnection of the tetrahedral cavities due to missing organic linkers greatly reduces the selectivity of the defected material.

adsorption
hydrocarbons
linker vacancies
metal–organic framework
separation

http://resolver.tudelft.nl/uuid:9eb88470-6fee-4aa9-863f-dac9809df985

https://doi.org/10.1002/chem.202200030

2023-07-01

0947-6539

Chemistry: A European Journal, 28 (29)

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

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© 2022 Andrzej Sławek, Gabriela Jajko, Karolina Ogorzały, David Dubbeldam, T.J.H. Vlugt, Wacław Makowski