Investigation of Pb(II) adsorption on a novel activated carbon prepared from hazelnut husk by K₂CO₃ activation

Abstract

Hazelnut husk, an agricultural waste, was used to prepare an activated carbon (HHPCAC) by chemical activation using K₂CO₃. HHPCAC was characterized by FT-IR spectroscopy, BET surface area determination, SEM, Boehm titration, proximate, and elemental analysis. HHPCAC has a high surface area (980.9 m²g⁻¹) and contains 2.60 mmol g⁻¹ of total acidic functional groups. HHPCAC was used for the removal of Pb(II) from aqueous solutions by investigating a number of effective factors such as initial pH, contact time, dosage, and initial concentration. Adsorption of Pb(II) ions is highly dependent on pH of the solution, and its optimal value was found to be 5.0. Time to equilibrium was found as 20 h. Kinetics of Pb(II) adsorption on HHPCAC followed pseudo-second-order model. Adsorption equilibrium data were analyzed by Langmuir and Freundlich models. Maximum adsorption capacity of HHPCAC for Pb(II) was calculated as 109.9 mg g⁻¹ using Langmuir equation. From the findings, it could be concluded that HHPCAC is a feasible adsorbent for the removal of Pb(II) ions from aqueous solutions.

Keywords:

• Adsorption
• Removal
• Activated carbon
• Hazelnut husk
• Lead
• Agricultural wastes

Acknowledgements

This work was supported partly by Sakarya University Scientific Research Foundation (Project number: 2010-02-04-018). Authors would like to thank Assist. Prof. Dr Yasemin Özdemir (Balıkesir Univ. Chemistry Dept., Turkey) for BET surface area determination and to Assist. Prof. Dr Esra Altıntığ (Sakarya Univ. Chemistry Dept., Turkey) for providing the furnace.