CONDUCTIVITY IN NA-MONTMORILLONITE AND LI+-MONTMORILLONITE AS A FUNCTION OF EQUILIBRATION HUMIDITY()

A considerable influence of relative humidity on the conductivity of s odium and lithium-montmorillonite was found. At high humidity the cond uctivity values are similar for both type of samples and higher than t hose measured at low humidity, whereas the activation energies show th e opposite relationship. In the low humidity zone the lithium-containi ng samples exhibit higher conductivity than that of the sodium ones. A n explanation is given based on the different nature of the sorbed wat er and on the hydration power of the Li+ and Na+ ions.