Time-resolved physicochemical characterization of MgO, SiO2, Cr2O3 and CdS in the presence of n-heptane

The reversed-flow gas chromatography (RF-GC), which is a version of inverse gas–solid chromatography (IGC) was used to measure the local adsorbed concentrations and the local adsorption energies on various active sites of the surface of MgO, SiO2, Cr2O3 and CdS for the adsorbed analyte n-heptane, and the local adsorption isotherms on these heterogeneous surfaces. All three above adsorption parameters mentioned above are calculated from chromatographic peaks as a function of the experimental time (a time-resolved analysis). The surface diffusion coefficients for all gas–solid systems mentioned above have been also determined experimentally.