RESUMO
The surface energy of exchanged forms of montmorillonite has been computed using a partial charge model introduced in the calculation of the lattice energy. The results are in correct agreement with data on heats of adsorption. However, the difference between theoretical and experimental data increases from light cations to heavy cations associated with the clay network. This indicates that the heat of adsorption depends highly on the step hydration of the cations. This type of behavior was expected and thus the quantification seems realistic.
RESUMO
This paper tries to assess simply and quantitatively the link between classical adsorption theories and dielectric spectroscopy, in order to demonstrate that dielectric spectroscopy can be used as a tool of determination of surface energy variations due to movements of charge carriers at the surface of solids. A simple theory is developed to analyze hops of cations at the surface of mordenite, which are detected by complex impedance spectroscopy during adsorption of water. An energy of extraction of the cation can be determined from measurements and its dependence on the quantity of water molecules adsorbed is shown and qualitatively and quantitatively explained, using relationships developed in order to interpret adsorption phenomena generally. The agreement with other determinations of the adsorption energies and solid surface energy is correct.
