Simultaneous adsorption of chlordimeform and Zn on montmorillonite

The organic and mineral components of the coloidal fraction of soils are the most active participants in the interface processes of adsorption-desorption, afecting organic chemicals presents in soils and aquatic systems. In many soils permanent charge minerals are predominant, and many adsorption properties are largely controlled by them, so that the reduction in the availability of some nutrients or pollutants, present in ionic form in soils is partially due to their adsorption on permanent charge surfaces. The purpose of this paper is to describe a part of our studies on the joint adsorption of pesticides and heavy metals by clay minerals. Here it is studied the simultaneous adsorption-desorption of the pesticide chlordimeform and Zn on Wyoming montmorillonite as a function of concentration of each adsorbate and of pH variation, and their effect on pesticide adsorption by clays. On the other hand, the interaction of Zn with mineral surfaces has a definite influence on the availability of Zn in soils, and consequently it is influenced also by the presence of the pesticide and its higher or lower facility to be adsorbed by clay minerals.