On the Electric Conductivity of Homoionic Montmorillonites at Low Water Content

Abstract

Bibliographic reports on the electric conductivity of pure homoionic montmorillonite at low water content were analyzed in order to stress a general behavior of conductivity. At low water content, the conductivity is attributed to a mechanism of charge transport involving protons due to the influence of the electric field of the exchangeable cations on water molecules at the solvation shell. Conductivity was analyzed in relation with the polarizing power (ionic potential) of the exchangeable cations and with the influence of the connectivity within samples. The general conclusion stressed is that the connectivity due to the association between 2:1 unit layers (clay fabric) is the main factor on the experimental or "macroscopic" electric conductivity of pure homoionic montmorillonite at low water content. Considerations on the experimental conditions of different bibliographic reports were also made. The conclusion and the considerations made on experimental conditions are a good starting point for future researches on electric conductivity of homoionic montmorillonite at low water content.