Conductance of Adsorbed Alkali Cations in Aqueous and Alcoholic Bentonite Pastes

Publisher Website
Google Scholar
Abstract
Equivalent conductivities of the alkali cations adsorbed on bentonite clay in water, and in methanol and ethanol gels, were determined and compared with their equivalent conductivities in bulk solution. The mobilities of adsorbed cations were reduced to about one‐half their mobilities in bulk solution in water systems and to much smaller fractions of their bulk solution mobilities in alcohol gels. The reduction in mobility was independent of the clay concentration in the range studied, and was characteristic of the cation. It was pointed out that “specific forces” between the cation and the clay surface are not possible unless the cations reside directly on the clay surface (without a watermolecule between the ion and the clay). The fraction of adsorbed cations not participating in electrical transport was in reasonable agreement with the portion of adsorbed ions residing directly on the surface as calculated considering both hydration and electrical potential energies in the Boltzmann distribution equation. An electrostatic interaction is discussed which would cause reduction in mobility of cations that are in the first molecular layer of solvent.
Funding Information
  • National Science Foundation

This publication has 2 references indexed in Scilit: