Ionic strentgh influence on heavy metal sorption processes by soil

Abstract
The sorption of Cd and Cu by three different European soils was studied in the presence of increasing concentration of CaCl ₂. Cd sorption fitted the Freundlich equation, while Cu fitted the Langmuir equation. Increasing ionic strength decreased the sorption of both metals, due to the competition of Ca ions for the sorption sites in the soils. The influence of ionic strength was related to the mechanisms of heavy metal sorption by the soil. The effect of increasing ionic strength was inversely related to organic matter content in soil.