Enthalpy of Adsorption for Hydrocarbons on Concrete by Inverse Gas Chromatography

Published

May 6, 2011

Author(s)

Jason A. Widegren, Thomas J. Bruno

Abstract

Enthalpies of adsorption, -Δ/H/_a ^0 , are reported for several light hydrocarbons on normal construction concrete. -Δ/H/_a ^0 , which describes the adhesion strength of a molecule on a surface, was determined by gas-solid chromatography with a packed column of 60-80 mesh concrete particles. With this approach the specific retention volume for a compound is measured as a function of temperature, and these data are used to calculate -Δ/H/_a ^0 . For the hydrocarbons studied, we found that -Δ/H/_a ^0 depended only weakly on branching. However, -Δ/H/_a ^0 was found to be relatively large for unsaturated compounds. The extent of dehydration affected the chromatographic behavior of the concrete column, which changed irreversibly above 473 K. These are the first determinations of -Δ/H/_a ^0 of hydrocarbons on concrete, but useful comparisons with other ionic solids like clays can be made. Our work with concrete is part of a larger project to study the surface energetics of a variety of chemicals on construction materials.

Citation

Journal of Chromatography A

Volume

1218

Pub Type

Journals

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Keywords

construction concrete, energetic material, enthalpy of adsorption, gas-solid chromatography, heat of adsorption, hydrocarbon

Citation

Widegren, J. and Bruno, T. (2011), Enthalpy of Adsorption for Hydrocarbons on Concrete by Inverse Gas Chromatography, Journal of Chromatography A, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=905950 (Accessed December 30, 2024)