Binding of heavy metal contaminants onto chitosans – An evaluation for remediation of metal contaminated soil and water

Kamari, A., Pulford, I.D. and Hargreaves, J.S.J. (2011) Binding of heavy metal contaminants onto chitosans – An evaluation for remediation of metal contaminated soil and water. Journal of Environmental Management, 92(10), pp. 2675-2682. (doi: 10.1016/j.jenvman.2011.06.005)

Abstract

The binding efficiency of chitosan samples for Ag⁺, Cd²⁺, Cu²⁺, Pb²⁺ and Zn²⁺ has been evaluated in order to consider their application to remediate metal contaminated soil and water. The sorption behaviour of metal ions was assessed using a batch technique at different contact time and initial metal concentration with different background electrolytes. The kinetics followed a pseudo-second-order model, while the equilibrium data correlated well with the Freundlich and Langmuir isotherm models. For example, the maximum sorption capacity (Q) for chitosan was estimated as 1.93 mmol/g for Ag⁺, 1.61 mmol/g for Cu²⁺, 0.94 mmol/g for Zn²⁺, 0.72 mmol/g for Cd²⁺ and 0.64 mmol/g for Pb²⁺. Covalent interaction between metal ions and functional groups (amino and hydroxyl) of the chitosans was the main binding mechanism. Ion exchange is not an important process. Chitosan and cross-linked chitosans were able to bind metal ions in the presence of K⁺, Cl⁻ and NO₃⁻. The nature of Cl⁻ and NO₃⁻ ions did not affect Zn²⁺ binding by the chitosans. Even at 11x dilution, the chitosans were able to retain metal ions on their surfaces.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hargreaves, Professor Justin and Pulford, Dr Ian
• Authors: Kamari, A., Pulford, I.D., and Hargreaves, J.S.J.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Journal of Environmental Management
• ISSN: 0301-4797
• Published Online: 25 June 2011