Kinetic model for adsorption and desorption of H2O and CO2 on hydrotalcite-based adsorbents

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

A comprehensive kinetic model was developed for the description of the sorption behavior of CO2, H2O and their interactions on potassium-promoted hydrotalcite-based sorbents. An Elovich-type equation has been used to describe the interactions of gas molecules with heterogeneous surface sites on the sorbent, accounting for the change in activation energy of desorption as a function of the surface coverage. The ability of the sorbent to desorb more CO2 while adsorbing H2O and vice versa was modeled with an additional adsorption site, assuming equimolar exchange between CO2 and H2O. A Freundlich isotherm was used to describe the change in adsorption capacity of CO2 and H2O as a function of the partial pressure of CO2 and H2O respectively, while the sorption capacity of the exchange site depends on both the CO2 and H2O partial pressures and could be described with a Freundlich type dependency for both CO2 and H2O. A good description of the desorption kinetics of both CO2 and H2O measured by extensive thermogravimetric analysis experiments has been obtained. The model is shown to adequately describe the complex sorption behavior at various experimental conditions between 300 and 500 °C and different partial pressures of the sorbate species CO2 and H2O and their mixtures. This is the first time that a kinetic model has been developed that can describe the adsorption and desorption kinetics of both CO2 and H2O including their complex interactions.

LanguageEnglish
Pages520-531
Number of pages12
JournalChemical Engineering Journal
Volume355
DOIs
StatePublished - 1 Jan 2019

Fingerprint

hydrotalcite
Carbon Monoxide
Adsorbents
Desorption
desorption
Sorbents
partial pressure
Partial pressure
adsorption
Sorption
Adsorption
kinetics
Kinetics
sorption
activation energy
Isotherms
Potassium
Thermogravimetric analysis
isotherm
potassium

Keywords

  • CO adsorption
  • Hydrotalcite sorbent
  • Kinetics
  • Model

Cite this

@article{22769729008545ea9c9f62d2f2fb2dbb,
title = "Kinetic model for adsorption and desorption of H2O and CO2 on hydrotalcite-based adsorbents",
abstract = "A comprehensive kinetic model was developed for the description of the sorption behavior of CO2, H2O and their interactions on potassium-promoted hydrotalcite-based sorbents. An Elovich-type equation has been used to describe the interactions of gas molecules with heterogeneous surface sites on the sorbent, accounting for the change in activation energy of desorption as a function of the surface coverage. The ability of the sorbent to desorb more CO2 while adsorbing H2O and vice versa was modeled with an additional adsorption site, assuming equimolar exchange between CO2 and H2O. A Freundlich isotherm was used to describe the change in adsorption capacity of CO2 and H2O as a function of the partial pressure of CO2 and H2O respectively, while the sorption capacity of the exchange site depends on both the CO2 and H2O partial pressures and could be described with a Freundlich type dependency for both CO2 and H2O. A good description of the desorption kinetics of both CO2 and H2O measured by extensive thermogravimetric analysis experiments has been obtained. The model is shown to adequately describe the complex sorption behavior at various experimental conditions between 300 and 500 °C and different partial pressures of the sorbate species CO2 and H2O and their mixtures. This is the first time that a kinetic model has been developed that can describe the adsorption and desorption kinetics of both CO2 and H2O including their complex interactions.",
keywords = "CO adsorption, Hydrotalcite sorbent, Kinetics, Model",
author = "K.T. Coenen and F. Gallucci and E.J.M. Hensen and {van Sint Annaland}, M.",
year = "2019",
month = "1",
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language = "English",
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Kinetic model for adsorption and desorption of H2O and CO2 on hydrotalcite-based adsorbents. / Coenen, K.T.; Gallucci, F.; Hensen, E.J.M.; van Sint Annaland, M.

In: Chemical Engineering Journal, Vol. 355, 01.01.2019, p. 520-531.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - Kinetic model for adsorption and desorption of H2O and CO2 on hydrotalcite-based adsorbents

AU - Coenen,K.T.

AU - Gallucci,F.

AU - Hensen,E.J.M.

AU - van Sint Annaland,M.

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AB - A comprehensive kinetic model was developed for the description of the sorption behavior of CO2, H2O and their interactions on potassium-promoted hydrotalcite-based sorbents. An Elovich-type equation has been used to describe the interactions of gas molecules with heterogeneous surface sites on the sorbent, accounting for the change in activation energy of desorption as a function of the surface coverage. The ability of the sorbent to desorb more CO2 while adsorbing H2O and vice versa was modeled with an additional adsorption site, assuming equimolar exchange between CO2 and H2O. A Freundlich isotherm was used to describe the change in adsorption capacity of CO2 and H2O as a function of the partial pressure of CO2 and H2O respectively, while the sorption capacity of the exchange site depends on both the CO2 and H2O partial pressures and could be described with a Freundlich type dependency for both CO2 and H2O. A good description of the desorption kinetics of both CO2 and H2O measured by extensive thermogravimetric analysis experiments has been obtained. The model is shown to adequately describe the complex sorption behavior at various experimental conditions between 300 and 500 °C and different partial pressures of the sorbate species CO2 and H2O and their mixtures. This is the first time that a kinetic model has been developed that can describe the adsorption and desorption kinetics of both CO2 and H2O including their complex interactions.

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