Temperature Extrapolation of Henry's Law Constants and the Isosteric Heat of Adsorption
Daniel Siderius, Harold Hatch, Vincent K. Shen
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.
, Hatch, H.
and Shen, V.
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)