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Updated: Jul 11, 2025
09:46
Adsorption Device Based on a Langatate Crystal Microbalance for High Temperature High Pressure Gas Adsorption in Zeolite H-ZSM-5
Published on: August 25, 2016
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On the Thermodynamic Condition for Adsorption Azeotropes.
Usman Hamid1, Chau-Chyun Chen1
1Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409-3121, United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|November 10, 2023
Summary
Researchers identified the thermodynamic condition for adsorption azeotropes, crucial for mixed-gas adsorption equilibria. This finding, derived from the generalized Langmuir isotherm, clarifies a long-standing puzzle in adsorption science.
Area of Science:
- Physical Chemistry
- Chemical Engineering
- Materials Science
Background:
- Adsorption azeotropy is a known phenomenon in mixed-gas adsorption equilibria, first reported in 1933.
- Previous studies on the thermodynamic conditions for adsorption azeotropes have not reached definitive conclusions.
Purpose of the Study:
- To present a thermodynamic condition for adsorption azeotropes derived from the generalized Langmuir isotherm model.
- To validate this condition with experimental data and explore influencing factors.
Main Methods:
- Utilized the generalized Langmuir isotherm model for multicomponent adsorption equilibria.
- Derived the thermodynamic condition for binary adsorption azeotropes: γ₁/K₁° = γ₂/K₂°.
- Validated the condition with 14 azeotrope-forming adsorption systems.
Main Results:
- Established the thermodynamic condition for adsorption azeotropes as the equality of the ratios of adsorbed phase activity coefficient and adsorption equilibrium constant for the two adsorbates.
- Demonstrated the analogy between adsorption azeotropy and vapor-liquid equilibrium azeotropy.
- Investigated the impact of pressure, temperature, and adsorbed phase nonideality on azeotrope formation.
Conclusions:
- The derived thermodynamic condition provides a clear criterion for predicting adsorption azeotropes.
- The generalized Langmuir model offers a robust framework for understanding mixed-gas adsorption phenomena.
- This work advances the fundamental understanding of adsorption equilibria and azeotrope formation.
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