Supercritical adsorption in micro- and meso-porous carbons and its utilisation for textural characterisation
| Autor: | Lisa Joss, J. P. Martin Trusler, Junyoung Hwang, Geoffrey C. Maitland, Ronny Pini, Humera Ansari |
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| Přispěvatelé: | Commonwealth Scientific and Industrial Research Organisation |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
02 engineering and technology General Chemistry Microporous material Lattice density functional theory 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Supercritical fluid 09 Engineering 0104 chemical sciences Adsorption Physisorption Chemical engineering Mechanics of Materials medicine General Materials Science Supercritical adsorption 0210 nano-technology Mesoporous material 03 Chemical Sciences Materials Activated carbon medicine.drug |
| Popis: | Understanding supercritical gas adsorption in porous carbons requires consistency between experimental measurements at representative conditions and theoretical adsorption models that correctly account for the solid’s textural properties. We have measured unary CO2 and CH4 adsorption isotherms on a commercial mesoporous carbon up to 25 MPa at 40 °C, 60 °C and 80 °C. The experimental data are successfully described using a model based on the lattice Density Functional Theory (DFT) that has been newly developed for cylindrical pores and used alongside Ar (87K) physisorption to extract the representative pore sizes of the adsorbent. The agreement between model and experiments also includes important thermodynamic parameters, such as Henry constants and the isosteric heat of adsorption. The general applicability of our integrated workflow is validated by extending the analysis to a comprehensive literature data set on a microporous activated carbon. This comparison reveals the distinct pore-filling behaviour in micro- and mesopores at supercritical conditions, and highlights the limitations associated with using slit-pore models for the characterisation of porous carbons with significant amounts of mesoporosity. The lattice DFT represents a departure from simple adsorption models, such as the Langmuir equation, which cannot capture pore size dependent adsorption behaviour, and a practical alternative to molecular simulations, which are computationally expensive to implement. |
| Databáze: | OpenAIRE |
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