Wetting and adsorption on organophilic illites and swelling montmorillonites in methanol-benzene mixtures

Adsorption and immersion were studied simultaneously in methanol-benzene mixtures on non-swelling organophilic illites and swelling organophilic montmorillonites. From the combination of adsroption and calorimetric data, equations were proposed for the determination of the adsorption capacity and the molar enthalpies of wetting differences, if the adsorption layer behaved ideally. From the experimental enthalpy isotherms of wetting and the enthalpy functions related to the ideal behaviour of the layer, qualitative conclusions were drawn on the excess enthalpy of the adsorpition layer. It was again established that the adsorption layer composed of alkyl chains, benzene and methanol has a regular cluster structure in certain concentration ranges, which breaks at higher methanol concentrations. This change is reflected by a significant endothermic peak of the differential molar enthalpy.For the organophilic montmorillonites, the enthalpy of swelling was determined separately as a function of the composition. The non-swelling organophilic illites were chosen as a reference system.Dedicated to Professor Dr. Armin Weiss on the occassion of his 60th birthday.