Adsorption of copper and zinc from aqueous solutions by using natural clay

In this study, removal of copper (CU2+) and zinc (Zn2+) from aqueous solutions is investigated using Cankiri bentonite, a natural clay. During the removal process, batch technique is used, and the effects of pH, clay amount, heavy metal concentration and agitation time on adsorption efficiency are studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms are applied in order to determine the efficiency of natural clay used as an adsorbent. Results show that all isotherms are linear. It is determined that adsorption of CU2+ and Zn2+ is well-fitted by the second order reaction kinetic. In addition, calculated and experimental heavy metal amounts adsorbed by the unit clay mass are too close to each other. It is concluded that natural clay can be used as an effective adsorbent for removing CU2+ and Zn2+ from aqueous solutions. (c) 2007 Elsevier B.V. All rights reserved.