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Temperature Extrapolation of Henry's Law Constants and the Isosteric Heat of Adsorption

Published

Author(s)

Daniel Siderius, Harold Hatch, Vincent K. Shen

Abstract

Computational screening of adsorbent materials often uses the Henry's law constant ($\KH$) (at a particular temperature) as a first discriminator metric due to its relative ease of calculation. The isosteric heat of adsorption in the limit of zero pressure ($\qstinf$) is often calculated along with the Henry's law constant, and both properties are informative metrics of adsorbent material performance at low pressure conditions. In this article, we introduce a method for extrapolating $\KH$ as a function of temperature, using series-expansion coefficients that are easily computed at the same time as $\KH$ itself; the extrapolation function also yields $\qstinf$. The extrapolation is highly accurate over a wide range of temperatures when the basis temperature is sufficiently high, for a wide range of adsorbent materials and adsorbate gases. Various results suggest that the extrapolation is accurate when the extrapolation range in inverse-temperature space is limited to $\left|\beta - \beta_0\right| < 0.5$mol/kJ. Application of the extrapolation to a large set of materials is shown to be successful provided that $\KH$ is not extremely large and/or the extrapolation coefficients converge satisfactorily. The extrapolation is also able to predict $\qstinf$ for a system that shows an unusually large temperature dependence. The work provides a robust method for predicting $\KH$ and $\qstinf$ over a wide range of industrially relevant temperatures with minimal effort beyond that necessary to compute those properties at a single temperature, which facilitates the addition of application temperature to computational screening exercises.
Citation
Journal of Physical Chemistry B
Volume
126
Issue
40

Keywords

adsorption, extrapolation, statistical mechanics, thermodynamics

Citation

Siderius, D. , Hatch, H. and Shen, V. (2022), Temperature Extrapolation of Henry's Law Constants and the Isosteric Heat of Adsorption, Journal of Physical Chemistry B, [online], https://doi.org/10.1021/acs.jpcb.2c04583, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935037 (Accessed February 3, 2023)
Created September 28, 2022, Updated November 29, 2022