Probability Density Function for Adsorption Energies over Time on Heterogeneous Surfaces by Inverse Gas Chromatography

The inverse gas chromatographic method of reversed-flow gas chromatography is extended to the measurement of the probability density function f(ε) for the adsorption energies on heterogeneous surfaces, as a function of the experimental time. The values of f(ε) are not found from the solution of an integral equation, but by their direct calculation from experimental data in a very simple way. The method is applied to the adsorption of (CH3)2S on CaCO3 and CaCO3 + C, in the presence and in the absence of NO2, at two temperatures around 303 and 323 K. The kinetic physicochemical parameters for the adsorption/desorption phenomena are also calculated for the above systems. The normalization of the f(ε) found, with respect to time, is easily done.