Effect of pH on Removal of Cu, Cd, Zn, and Ni by Cement Kiln Dust in Aqueous Solution

ABSTRACT

A batch experiment was conducted to study the effect of pH on the sorption of copper (Cu), cadmium (Cd), zinc (Zn), and nickel (Ni) by cement kiln dust (CKD). The experiment was carried out by adding 25 mL of solutions containing concentrations of 200, 400, 600, 800, and 1000 mg/L of each of these heavy metal cations to 1.00 g of CKD. The pH of these suspensions was adjusted to 2, 5, and 7 as well as non-adjusted. The sorbed amount (Cs) and the sorption percentage of Cu, Cd, Zn, and Ni by CKD increased with increasing the suspension pH. The adsorption data of Cu, Cd, Zn, and Ni were generally well correlated with Langmuir model when the suspension pH was adjusted to 5, 7, non-adjusted and 7, respectively. However, they could be well described by Freundlich model when the suspension pH was adjusted to 5, 2, non-adjusted and 5, respectively.

KEYWORDS:

• Cement kiln dust
• Freundlich
• heavy metals
• Langmuir
• sorption

Acknowledgments

The authors’ sincere thanks and appreciation to Dr. M.A. El-Desoky, professor of soil sciences, Department of Soils and Water, Faculty of Agriculture, Assiut University, Egypt, for his linguistic correction for this manuscript.