Influence of pH and Ionic Strength on the Adsorption of Copper and Zinc in Bentonite Clay

Abstract

This study concerned with the possibility of adsorption of some metal cations such as Cu 2+ and Zn 2+ on bentonite ore which were used as an inorganic fertilizer. Maximum adsorption was obtained at pH 5-5.5. The relationship between the amounts of metal cations adsorbed was found to follow the Freundlich adsorption isotherm. Preferential adsorption of both ions on adsorption sites was found to take place; Cu 2+ is being adsorbed at greater extent than Zn 2+ . Bentonite samples which allowed adsorbing Cu 2+ and Zn 2+ were then subjected to desorption experiments using EDTA/OAc. Sequential leaching of the adsorbed ions revealed that the amounts of desorbed ion are linearly proportional to the amount previously adsorbed.