Biosorption of zinc ions onto Corylus avellana L.

Abstract

Hazelnut is one of the most important agricultural products of Turkey. North coasts of Turkey are so suitable to grow hazelnut that approximately 80% of the total hazelnut production in the world is supplied from this region. There is a great potential of woody hazelnut shell (obtained from species of Corylus avellana L.) to use in some applications in that region. Sorption studies are one of these. For this reason in this paper, batch adsorption of Zn²⁺ ions onto ground and sieved hazelnut shells was studied in comparable with sawdust of various species of wood and in order to explore the potential use of this material as low cost adsorbent for heavy metal removal in industrial effluents. The capacity of the adsorption for the removal of zinc ions from aqueous solution was investigated under different conditions such as solution contact time (1–360 min), particle size (–75, 75–150 and 150–200 μm), temperature of solution (25 °C–60 °C) and solution pH (3–7). Moreover, zeta potential of particles at different initial pHs (2–10) was measured. The equilibrium data were processed according to Langmuir and Freundlich’s isotherm models and higher adsorption capacity values towards Zn²⁺ ions were shown. The adsorption kinetics was investigated and the best fit was achieved by a pseudo-second-order equation.

Keywords:

• Adsorption
• Kinetics
• Hazelnut shell
• Zeta potential
• Zinc ion

Acknowledgments

The authors thank the support from Balikesir University Research Foundation (Project No: BAP(2008/26) and the Balikesir University Research Center of Applied Science (BURCAS) for the zeta potential measurements and SEM images is gratefully acknowledged.