Authors: ABİDİN KAYA
Abstract: The electrical conductivity and dielectric permittivity of clay-water systems were used to characterize the physicochemical state of kaolin and bentonite-water systems. The dielectric permittivity and electrical conductivity of kaolin and bentonite were determined at various water contents and NaCl concentrations as a function of frequency, ranging from 0.1 kHz to 13 MHz. The results indicate that kaolin and bentonite have similar dielectric behavior. An increase in the frequency produces a decrease in the dielectric permittivity of the soil-pore water mixture. As the ion concentration increases, the dielectric permittivity of the mixture increases at low frequency (kHz) whereas it decreases at high frequency (MHz). The electrical conductivity of kaolin and bentonite increases with an increase in the ion concentration in the soil-water mixture. The electrical conductivity of a kaolin-water mixture decreases with an increase in the solid concentration. In contrast, the electrical conductivity of a bentonite-water mixture increases with a decrease in the solid concentration. This indicates the importance of the surface conductivity of a bentonite-water mixture. Furthermore, the results of this study indicate that dielectric permittivity and electrical conductivity might be used to characterize the electrokinetic behavior of soil minerals to determine the physiochemical changes in clay soil-water systems, such as subsurface contaminations.
Keywords: bentonite, contamination, dielectric permittivity, electrical conductivity, kaolin, slurry
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