Title: Framework Breathing in the Vapour-Phase Adsorption and Separation of Xylene Isomers with the Metal-Organic Framework MIL-53
Authors: Finsy, Vincent ×
Kirschhock, Christine
Vedts, Gill
Maes, Michaƫl
Alaerts, Luc
De Vos, Dirk
Baron, Gino V
Denayer, Joeri F. M #
Issue Date: 2009
Publisher: VCH Verlagsgesellschaft
Series Title: Chemistry - a European Journal vol:15 issue:31 pages:7724-7731
Abstract: Vapour-phase adsorption and separation of the C8 alkyl aromatic compounds p-xylene, m-xylene, o-xylene, and ethylbenzene has been studied on the metal-organic framework MIL-53. Adsorption and desorption isotherms of the pure components at 110 degrees C were determined using the gravimetric technique. The adsorption isotherms show two well-defined steps and hysteresis, corresponding to the opening or breathing of the framework, as induced by the presence of the adsorbing molecules. In the first isotherm plateau, an adsorption capacity of about 18 wt% is observed. After the breathing phenomenon, the adsorption capacity increases to about 40wt%. Breakthrough separation experiments with equimolar o-xylene/ethylbenzene mixtures were performed at 110 degrees C with varying hydrocarbon pressures. The separation mechanism is related to the state of the pore structure, as dictated by framework breathing. At low pressure, below the "pore-opening" pressure, MIL-53 shows no preference for any isomer. At pressures high enough to induce pore opening, separation of the C8 alkyl aromatic isomers becomes possible and separation factors as high as 6.5 are observed. The separation at a high degree of pore filling in the open form is a result of differences in the packing modes of the CS alkyl aromatic components in the pores of MIL-53.
ISSN: 0947-6539
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Centre for Surface Chemistry and Catalysis
× corresponding author
# (joint) last author

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