Capacity of adsorption of Pb and Ni from aqueous solutions by chitosan produced from silkworm chrysalides in different degrees of deacetylation

The binding capacities of chitin (CT) and chitosan (CS) produced from silkworm chrysalides were investigated aiming at their future application in the removal of Pb2+ and Ni2+ from wastewaters. CS with 75% deacetylation degree (DD) exhibited good binding performance for Pb2+, but bad efficiency for...

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Bibliographic Details
Published in:Journal of hazardous materials 2007-08, Vol.147 (1-2), p.139-147
Main Authors: Paulino, Alexandre T, Guilherme, Marcos R, Reis, Adriano V, Tambourgi, Elias B, Nozaki, Jorge, Muniz, Edvani C
Format: Article
Language:English
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Summary:The binding capacities of chitin (CT) and chitosan (CS) produced from silkworm chrysalides were investigated aiming at their future application in the removal of Pb2+ and Ni2+ from wastewaters. CS with 75% deacetylation degree (DD) exhibited good binding performance for Pb2+, but bad efficiency for Ni2+. The maximum binding capacity obtained from isotherms for CSPb was 141.10mgg-1 and 52.81mgg-1 for CSNi. The binding capacities for CT were 32.01mgg-1 for Pb2+ and 61.24mgg-1 for Ni2+. The authors attribute these behaviors to two main factors: (i) the large ionic size of Pb2+ and (ii) the steric hindrance due to CT acetyl groups. Metal binding onto CS was evaluated by the Freundlich and Langmuir isotherm models. The parameter values obtained from the isotherm analysis confirmed that Pb2+ and Ni2+ interact differently with CS and that various factors influence their adsorption. Thermogravimetric analysis (TGA) showed that the thermal behavior of CS with 75% deacetylation degree was in the same profile of standard CS; however, the binding of the metals onto its structure affects the curve profile.
ISSN:0304-3894
DOI:10.1016/j.jhazmat.2006.12.059