Fitting of unary isotherms in MOFs and zeolites: Are saturation capacities and Freundlich exponents temperature-dependent?
- 1Van ‘t Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
Abstract
Microporous crystalline adsorbents such as zeolites, and metal-organic frameworks (MOFs) have potential use in a wide variety of separations applications. The evaluation of the separation performance requires the measurement of data on unary isotherms of the guest molecules in the microporous host materials; such measurements are usually conducted for a range of temperatures. The experimental data on the unary isotherms may be fitted with a variety of models such as 1-site Langmuir , 1-site Langmuir-Freundlich, and Dual-Site Langmuir-Freundlich (DSLF). The fitted isotherms are then used for calculation of the adsorption selectivity, , using the Ideal Adsorbed Solution Theory (IAST). The isotherm fits at different temperatures allow the determination of the isosteric heats of adsorption . By careful and detailed examination of the experimental data of more than sixty guest/host combinations at different temperatures, we conclude that the saturation capacities and Freundlich exponents are essentially temperature-independent. For any guest/host combination, the optimal fits of the sets of unary isotherm data at different temperatures are achieved by constraining the the saturation capacities and Freundlich exponents to be temperature-independent. Plotting the unary isotherm data at different temperatures as function of the surface potential results in a unique curve.
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BibTeX
@article{krishna2026fitting,
title = {{Fitting of unary isotherms in MOFs and zeolites: Are saturation capacities and Freundlich exponents temperature-dependent?}},
author = {Rajamani Krishna},
journal = {Results in Engineering},
year = {2026},
month = jul,
doi = {10.1016/j.rineng.2026.111813},
url = {https://doi.org/10.1016/j.rineng.2026.111813},
note = {CC BY},
}
RIS
TY - JOUR
TI - Fitting of unary isotherms in MOFs and zeolites: Are saturation capacities and Freundlich exponents temperature-dependent?
AU - Rajamani Krishna
PY - 2026
DA - 2026/07/01
JO - Results in Engineering
DO - 10.1016/j.rineng.2026.111813
UR - https://doi.org/10.1016/j.rineng.2026.111813
AB - Microporous crystalline adsorbents such as zeolites, and metal-organic frameworks (MOFs) have potential use in a wide variety of separations applications. The evaluation of the separation performance requires the measurement of data on unary isotherms of the guest molecules in the microporous host materials; such measurements are usually conducted for a range of temperatures. The experimental data on the unary isotherms may be fitted with a variety of models such as 1-site Langmuir , 1-site Langmuir-Freundlich, and Dual-Site Langmuir-Freundlich (DSLF). The fitted isotherms are then used for calculation of the adsorption selectivity, , using the Ideal Adsorbed Solution Theory (IAST). The isotherm fits at different temperatures allow the determination of the isosteric heats of adsorption . By careful and detailed examination of the experimental data of more than sixty guest/host combinations at different temperatures, we conclude that the saturation capacities and Freundlich exponents are essentially temperature-independent. For any guest/host combination, the optimal fits of the sets of unary isotherm data at different temperatures are achieved by constraining the the saturation capacities and Freundlich exponents to be temperature-independent. Plotting the unary isotherm data at different temperatures as function of the surface potential results in a unique curve.
SN - 2590-1230
ER -