title: Binding of heavy metal contaminants onto chitosans--an evaluation for remediation of metal contaminated soil and water.
abstract: The binding efficiency of chitosan samples for Ag(+), Cd(2+), Cu(2+), Pb(2+) and Zn(2+) 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 Cu(2+), 0.94 mmol/g for Zn(2+), 0.72 mmol/g for Cd(2+) and 0.64 mmol/g for Pb(2+). 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 NO(3)(-). The nature of Cl(-) and NO(3)(-) ions did not affect Zn(2+) binding by the chitosans. Even at 11x dilution, the chitosans were able to retain metal ions on their surfaces.
authors.affiliation: WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: A
authors.initials: A
authors.lastname: Kamari
authors.forename: I D
authors.initials: ID
authors.lastname: Pulford
authors.forename: J S J
authors.initials: JS
authors.lastname: Hargreaves
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007700:Kinetics; D019216:Metals, Heavy / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D014873:Water Pollutants / Q000737:chemistry*
chemical_list: D004573:Electrolytes; D019216:Metals, Heavy; D012989:Soil Pollutants; D014873:Water Pollutants; D048271:Chitosan