SIMULTANEOUS ADSORPTION OF CADMIUM AND A CATIONIC PESTICIDE ON MONTMORILLONITE

The competitive adsorption of the cationic pesticide chlordimeform and the heavy metal cadmium on montmorillonite was studied. For the diffe rent pesticide concentrations used, cadmium adsorption decreases with increasing chlordimeform concentration, indicating a high competition between both cations for interlamellar positions. In contrast, pestici de adsorption increases in the presence of Cd2+ in relation to Cd-free treatments. This adsorption is independent of metal concentration use d, and therefore adsorption isotherms are practically the same in all cases where cadmium is present.