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|Type:||Artigo de periódico|
|Title:||Capacity of adsorption of Pb2+ and Ni2+ from aqueous solutions by chitosan produced from silkworm chrysalides in different degrees of deacetylation|
|Abstract:||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 Ph2+ butbad efficiency for Ni2+. The maximum binding capacity obtained from isotherms for CS-Pb was 141. 10 mg g(-1) and 52.81 mg g(-1) for CS-Ni. The binding capacities for CT were 32.01 mg g(-1) for Ph2+ and 61.24 mg g for Ni2l. The authors attribute these behaviors to two main factors: (i) the large ionic size of Ph2+ 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 Ph2+ 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. (c) 2007 Elsevier B.V. All rights reserved.|
|Editor:||Elsevier Science Bv|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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