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Title: Vibrational and thermodynamic study of the adsorption of carbon dioxide on the zeolite Na-ZSM-5

Abstract

Microcalorimetry and vibrational spectroscopy have jointly been used to study the interaction at room temperature between CO{sub 2} and Na-ZSM-5. This interaction consists of a reversible, two-step adsorption on sites approximately all equal and noninteracting, which constitute an ideal ensemble in the thermodynamic sense. From the volumetric and calorimetric adsorption isotherms, standard changes in enthalpy and Gibbs free energy due to adsorption were calculated for both the 1:1 and 2:1 adducts formed by CO{sub 2} and Na{sup +} ions, and from these data, the standard changes in entropy were determined. All vibrational modes of adsorbed CO{sub 2} have been measured, including the usually elusive intermolecular ones, thus allowing the entropy of the adsorbed phase to be calculated by means of statistical mechanics. The vibrational modes of the carbon dioxide molecule are only slightly perturbed from the corresponding values for the gas phase. The most prominent {nu}{sub 3} mode is at 2,356 cm{sup {minus}1} in the 1:1 adduct and at 2,352 cm{sup {minus}1} in the 2:1 adduct, as compared to 2,349 cm{sup {minus}1} in the gas phase. The {nu}{sub 1} and {nu}{sub 2} modes are at 1,382 and 656 cm{sup {minus}1} for both adducts (1,388 and 667 cm{sup {minus}1}, respectively, inmore » the gas phase). Comparison between volumetric and optical adsorption isotherms has allowed the estimate of the related molar adsorption coefficients for all vibrational modes of the two adducts, with the exception of the corresponding value for the {nu}{sub 3} mode in the 2:1 adduct, because the related band is exceedingly intense.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Univ. di Torino (IT)
OSTI Identifier:
20080286
Resource Type:
Journal Article
Journal Name:
Langmuir
Additional Journal Information:
Journal Volume: 16; Journal Issue: 11; Other Information: PBD: 30 May 2000; Journal ID: ISSN 0743-7463
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; ZEOLITES; CARBON DIOXIDE; THERMODYNAMICS; ADSORPTION

Citation Formats

Bonelli, B., Onida, B., Fubini, B., Arean, C.O., and Garrone, E. Vibrational and thermodynamic study of the adsorption of carbon dioxide on the zeolite Na-ZSM-5. United States: N. p., 2000. Web. doi:10.1021/la991363j.
Bonelli, B., Onida, B., Fubini, B., Arean, C.O., & Garrone, E. Vibrational and thermodynamic study of the adsorption of carbon dioxide on the zeolite Na-ZSM-5. United States. doi:10.1021/la991363j.
Bonelli, B., Onida, B., Fubini, B., Arean, C.O., and Garrone, E. Tue . "Vibrational and thermodynamic study of the adsorption of carbon dioxide on the zeolite Na-ZSM-5". United States. doi:10.1021/la991363j.
@article{osti_20080286,
title = {Vibrational and thermodynamic study of the adsorption of carbon dioxide on the zeolite Na-ZSM-5},
author = {Bonelli, B. and Onida, B. and Fubini, B. and Arean, C.O. and Garrone, E.},
abstractNote = {Microcalorimetry and vibrational spectroscopy have jointly been used to study the interaction at room temperature between CO{sub 2} and Na-ZSM-5. This interaction consists of a reversible, two-step adsorption on sites approximately all equal and noninteracting, which constitute an ideal ensemble in the thermodynamic sense. From the volumetric and calorimetric adsorption isotherms, standard changes in enthalpy and Gibbs free energy due to adsorption were calculated for both the 1:1 and 2:1 adducts formed by CO{sub 2} and Na{sup +} ions, and from these data, the standard changes in entropy were determined. All vibrational modes of adsorbed CO{sub 2} have been measured, including the usually elusive intermolecular ones, thus allowing the entropy of the adsorbed phase to be calculated by means of statistical mechanics. The vibrational modes of the carbon dioxide molecule are only slightly perturbed from the corresponding values for the gas phase. The most prominent {nu}{sub 3} mode is at 2,356 cm{sup {minus}1} in the 1:1 adduct and at 2,352 cm{sup {minus}1} in the 2:1 adduct, as compared to 2,349 cm{sup {minus}1} in the gas phase. The {nu}{sub 1} and {nu}{sub 2} modes are at 1,382 and 656 cm{sup {minus}1} for both adducts (1,388 and 667 cm{sup {minus}1}, respectively, in the gas phase). Comparison between volumetric and optical adsorption isotherms has allowed the estimate of the related molar adsorption coefficients for all vibrational modes of the two adducts, with the exception of the corresponding value for the {nu}{sub 3} mode in the 2:1 adduct, because the related band is exceedingly intense.},
doi = {10.1021/la991363j},
journal = {Langmuir},
issn = {0743-7463},
number = 11,
volume = 16,
place = {United States},
year = {2000},
month = {5}
}