Studies of the state of benzene molecules adsorbed on the surface of organoderivatives of kaolinite and silica

The adsorption–calorimetric method is used to study the adsorption values and adsorption heats of benzene at the modified kaolinite and silica samples. The entropy diagrams of the benzene adsorbed at these samples are calculated. The results are compared with the entropy losses calculated from the ideal models of localised and non-localised adsorption. It is shown that the nature of the inorganic matrix, the modifier type and the modification degree determine the character of the benzene sorption on the studied sorbents, which can be described either by the supermobile model, non-localised model or non-localised model with partial loss of rotational degrees of freedom. For an infrequent case of supermobile adsorption of benzene at the modified silica, the frequencies of the vibrations of the molecule perpendicular to the surface are calculated.