Adsorption of Cu(II) on natural and treated clays

We have studied the pH and the temperature effects on copper ions' adsorption on natural and treated clays from Algeria. The clay was also treated to improve the adsorption capacity. X-ray diffraction identified montmorillonite and kaolinite as major clay minerals. The Langmuir adsorption model was used for the mathematical description of the adsorption equilibrium and the equilibrium data adhered very well to this model. The treated and natural clay had a monolayer adsorption capacity equal to 15.40 and 12.22 mg/g, respectively, at pH value of 6.5 and temperature 20 °C, the adsorption isotherms could be fitted with Langmuir isotherms, and the coefficients indicated favorable adsorption of Cu(II) on the clays. Determination of the thermodynamic parameters, H, S , and G showed that the adsorption process was spontaneous and exothermic accompanied by a decrease in entropy and Gibbs energy. Results of this study will be useful for future scale-up for using this material as a low-cost adsorbent for the removal of Cu(II) from wastewater.