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|Author(s):||Jason A. Widegren; Thomas J. Bruno;|
|Title:||Enthalpy of Adsorption for Hydrocarbons on Concrete by Inverse Gas Chromatography|
|Published:||May 06, 2011|
|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|
|Pages:||pp. 4474 - 4477|
|Keywords:||construction concrete, energetic material, enthalpy of adsorption, gas-solid chromatography, heat of adsorption, hydrocarbon|
|Research Areas:||Forensics, Thermophysics|