Removal of cadmium from aqueous solutions by walnut green husk as a low-cost biosorbent

Abstract

In this study, the removal of Cd(II) ions by walnut green husk particles has been investigated by batch technique. The effect of initial solution pH, initial concentration of dissolved Cd(II), amount of adsorbent, and contact time on the removal efficiency and adsorption capacity were studied. The adsorption process was pH dependent, and the maximum adsorption of analyte was achieved at pH 7. Adsorption test results revealed that Cd(II) adsorption on the studied adsorbent could be fitted to Langmuir and Freundlich isotherms. The optimum amount of adsorbent was found to be 0.8 g L⁻¹ of sample solution with initial Cd(II) concentration of 1.5 mg L⁻¹ (i.e. 5.33 g L⁻¹ for 10 mg L⁻¹ Cd). In the optimum conditions, the removal efficiency of Cd(II) turned out to be 96.11%.

Keywords:

• Biosorbent
• Walnut green husk particles
• Heavy metal
• Cadmium

Acknowledgments

The authors express their appreciation to the Graduate School and Research Council of University of Zanjan for financial support of this work. They also thank Dr H. Aliasin, from the English Department of the University, for proofreading the manuscript.