Enthalpy-entropy compensation for n-hexane adsorption on HZSM-5 containing transition metal ions
Abstract
In this work, the values of entropy changes related to n-hexane adsorption onto ion-exchanged ZSM-5 zeolites were calculated from differential heats, obtained from microcalorimetric experiments. The existence of enthalpy-entropy compensation effect, evidenced by the linearity of -Lambda H vs. -Lambda S plots and characteristic for all investigated ZSM-5 zeolites, was found. In the case of ZSM-5 structure, modifying the zeolite structure by ion-exchange gives rise to changes in the heats of adsorption and adsorption entropy in the same manner. The factors that can influence the appearance of entropy-enthalpy compensation were discussed. It was found that compensation effect is governed by ion-induced dipole interaction between highly polarizing cationic centres in zeolite and nonopolar n-hexane molecules, and hence, depends on the size, charge and electron configuration of the cation. It was found also that the compensation temperature is in correlation with the number of zeolites' stro...ng acid centres. Contrary to the adsorption of n-hexane on ZSM-5 zeolites, compensation effect was not found for the adsorption of the same gas on faujasite-type zeolites.
Keywords:
Enthalpy-entropy compensation / Compensation temperatures / Microcalorimetry / Zeolites / ZSM-5Source:
Journal of Chemical Thermodynamics, 2012, 48, 112-117Publisher:
- Academic Press Ltd- Elsevier Science Ltd, London
Funding / projects:
DOI: 10.1016/j.jct.2011.12.016
ISSN: 0021-9614
WoS: 000300416700015
Scopus: 2-s2.0-84857052007
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Institution/Community
Poljoprivredni fakultetTY - JOUR AU - Hercigonja, Radmila AU - Rac, Vladislav AU - Rakić, Vesna AU - Auroux, Aline PY - 2012 UR - http://aspace.agrif.bg.ac.rs/handle/123456789/2994 AB - In this work, the values of entropy changes related to n-hexane adsorption onto ion-exchanged ZSM-5 zeolites were calculated from differential heats, obtained from microcalorimetric experiments. The existence of enthalpy-entropy compensation effect, evidenced by the linearity of -Lambda H vs. -Lambda S plots and characteristic for all investigated ZSM-5 zeolites, was found. In the case of ZSM-5 structure, modifying the zeolite structure by ion-exchange gives rise to changes in the heats of adsorption and adsorption entropy in the same manner. The factors that can influence the appearance of entropy-enthalpy compensation were discussed. It was found that compensation effect is governed by ion-induced dipole interaction between highly polarizing cationic centres in zeolite and nonopolar n-hexane molecules, and hence, depends on the size, charge and electron configuration of the cation. It was found also that the compensation temperature is in correlation with the number of zeolites' strong acid centres. Contrary to the adsorption of n-hexane on ZSM-5 zeolites, compensation effect was not found for the adsorption of the same gas on faujasite-type zeolites. PB - Academic Press Ltd- Elsevier Science Ltd, London T2 - Journal of Chemical Thermodynamics T1 - Enthalpy-entropy compensation for n-hexane adsorption on HZSM-5 containing transition metal ions EP - 117 SP - 112 VL - 48 DO - 10.1016/j.jct.2011.12.016 ER -
@article{ author = "Hercigonja, Radmila and Rac, Vladislav and Rakić, Vesna and Auroux, Aline", year = "2012", abstract = "In this work, the values of entropy changes related to n-hexane adsorption onto ion-exchanged ZSM-5 zeolites were calculated from differential heats, obtained from microcalorimetric experiments. The existence of enthalpy-entropy compensation effect, evidenced by the linearity of -Lambda H vs. -Lambda S plots and characteristic for all investigated ZSM-5 zeolites, was found. In the case of ZSM-5 structure, modifying the zeolite structure by ion-exchange gives rise to changes in the heats of adsorption and adsorption entropy in the same manner. The factors that can influence the appearance of entropy-enthalpy compensation were discussed. It was found that compensation effect is governed by ion-induced dipole interaction between highly polarizing cationic centres in zeolite and nonopolar n-hexane molecules, and hence, depends on the size, charge and electron configuration of the cation. It was found also that the compensation temperature is in correlation with the number of zeolites' strong acid centres. Contrary to the adsorption of n-hexane on ZSM-5 zeolites, compensation effect was not found for the adsorption of the same gas on faujasite-type zeolites.", publisher = "Academic Press Ltd- Elsevier Science Ltd, London", journal = "Journal of Chemical Thermodynamics", title = "Enthalpy-entropy compensation for n-hexane adsorption on HZSM-5 containing transition metal ions", pages = "117-112", volume = "48", doi = "10.1016/j.jct.2011.12.016" }
Hercigonja, R., Rac, V., Rakić, V.,& Auroux, A.. (2012). Enthalpy-entropy compensation for n-hexane adsorption on HZSM-5 containing transition metal ions. in Journal of Chemical Thermodynamics Academic Press Ltd- Elsevier Science Ltd, London., 48, 112-117. https://doi.org/10.1016/j.jct.2011.12.016
Hercigonja R, Rac V, Rakić V, Auroux A. Enthalpy-entropy compensation for n-hexane adsorption on HZSM-5 containing transition metal ions. in Journal of Chemical Thermodynamics. 2012;48:112-117. doi:10.1016/j.jct.2011.12.016 .
Hercigonja, Radmila, Rac, Vladislav, Rakić, Vesna, Auroux, Aline, "Enthalpy-entropy compensation for n-hexane adsorption on HZSM-5 containing transition metal ions" in Journal of Chemical Thermodynamics, 48 (2012):112-117, https://doi.org/10.1016/j.jct.2011.12.016 . .