Analytic Expressions for the Isosteric Heat of Adsorption from Adsorption Isotherm Models and 2D SAFT-VR EoS
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• Flor Siperstein,
• Carlos Avendaño,
• Jordan Ortiz,
• Alejandro Gil-Villegas
Flor Siperstein
The University of Manchester
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Carlos Avendaño
The University of Manchester
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Jordan Ortiz
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Alejandro Gil-Villegas
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Abstract

The isosteric heat of adsorption is an important thermodynamic property used to characterise and optimise adsorption processes. In this work, analytic expressions for isosteric heats of adsorption are derived for a collection of commonly used isotherm models and a two-dimensional molecular equation of state based on the SAFT-VR approach. The use of these expressions is presented with an example of adsorption of nitrous oxide, N$${}_{2}$$O, on biochar, which is a waste biomass charcoal that exhibits high adsorption potential. The results show that accurate fitting of the adsorption isotherms leads to consistent results obtained with different approaches, however, the predicted isosteric heat of adsorption exhibits strong variations in the regions where experimental data is insufficient such in the region of low pressure/low coverage. Convergence on the prediction of the isosteric heat of adsorption by the different models is only observed in the region where no extrapolation of experimental data is needed.

Peer review status:ACCEPTED

02 Jun 2020Submitted to AIChE Journal
02 Jun 2020Submission Checks Completed
02 Jun 2020Assigned to Editor
11 Jun 2020Reviewer(s) Assigned
23 Nov 2020Editorial Decision: Revise Minor