Potential Measurements Used to Study the Bentonite-Pollutant and Kaolin-Pollutant Interphase

To support the application of an electrokinetic treatment to clay soils polluted with metals, a study of the interphase soil-pollutant-soil solution was carried out based on Zeta Potential (ζ) measurements. The physicochemical and transport phenomena that occur during electrokinetic treatment due to the soil-pollutant interaction at different electrolytes can be deduced from the ζ values. The experimental work begins with the physicochemical characterization of two clays: Bentonite (B) and Kaolin (K). Both samples were converted to homoionic form in order to observe the superficial adsorption of cations. 1M solutions of (NH4)2SO4, NH4Cl and CuSO4, CuCl2 were chosen for this purpose. Copper concentration, cation exchange capacity (CEC) and ζ were analyzed in the homoionic samples to study the soil-pollutant interaction. Results show that the adsorption/desorption process can be studied by the ζ values; these values reflect the chemical changes at the soil-pollutant-soil solution interphase.