Contribution to the study of the complexation of copper by chitosan and oligomers

Rhazi, Mohammed; Desbrières, Jacques; Tolaimate, A.; Rinaudo, Marguerite; Vottero, P.; Alagui, Abdelhakim

doi:10.1016/s0032-3861(01)00685-1

Cited by 224 publications

(142 citation statements)

References 34 publications

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“…The same solution with an excess of metal (Zn as a model) showed a different scattering profile in which a signal responsible for the 99.8% of the polymer agglomerate mass has a larger radius (1.107 nm) and a significantly decreased diffusion coefficient (2.22·10 -6 cm 2 s -1 ). This finding supports the hypothesis of a foldedlike structure being formed between the CMCH and Zn [29,30].…”

supporting

confidence: 89%

Interaction of carboxymethylchitosan and heavy metals in cement media

Lasheras-Zubiate

Navarro-Blasco

Álvarez

et al. 2011

Journal of Hazardous Materials

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The performance of an etherified chitosan, carboxymethyl chitosan (CMCH), when added to cement mortars doped with heavy metals, was assessed. In the presence of heavy metals (Cr, Pb, Zn) strong modifications of the fresh-state properties were evaluated. The addition of the polymer was seen to be useful in minimising some of these modifications, as those related to the setting time. A competitive mechanism for adsorption between the oxoanionic form of the metals and the carboxylate groups of the chitosan derivative was established. Studies on the metal chelating ability of the polymer and leaching from the hardened specimens showed scarce complexation under alkaline conditions, pointing to physical entrapment based on metal adsorption. However, significant chelation of metals was proved at near-neutral pH, suggesting the potential usefulness of the polymer as a agent for removing heavy metals from polluted waters and subsequently immobilizing them in cement mortars. Leaching tests carried out on polymer-metal complex-bearing samples showed a significant reduction in the amount of released Pb and Zn.

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supporting

confidence: 89%

Interaction of carboxymethylchitosan and heavy metals in cement media

Lasheras-Zubiate

Navarro-Blasco

Álvarez

et al. 2011

Journal of Hazardous Materials

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“…Os espectros de ressonância magnética nuclear de 13 C no estado sólido foram obtidos mediante espectrômetro AC300/P Brucker com ângulo mágico, operando em CP/MAS em 75,47 MHz, com tempo de relaxação de 4 s e tempo de contato de 1 ms, não sendo necessário quaisquer tratamentos prévio das amostras.…”

Section: Caracterizaçãounclassified

O emprego de quitosana quimicamente modificada com anidrido succínico na adsorção de azul de metileno

Lima¹,

Ribeiro²,

Airoldi³

2006

Quím. Nova

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Recebido em 13/4/05; aceito em 29/8/05; publicado na web em 8/2/06 THE USE OF CHEMICALLY MODIFIED CHITOSAN WITH SUCCINIC ANHYDRIDE IN THE METHYLENE BLUE ADSORPTION. The adsorption capacity of α-chitosan and its modified form with succinic anhydride was compared with the traditional adsorbent active carbon by using the dye methylene blue, employed in the textile industry. The isotherms for both biopolymers were classified as SSA systems in the Giles model, more specifically in L class and subgroup 3. The dye concentration in the supernatant in the adsorption assay was determined through electronic spectroscopy. By calorimetric titration thermodynamic data of the interaction between methyene blue and the chemically modified chitosan at the solid/liquid interface were obtained. The enthalpy of the dye/chitosan interaction gave 2.47 ± 0.02 kJ mol -1 with an equilibrium constant of 7350 ± 10 and for the carbon/dye interaction this constant gave 5951 ± 8. The spontaneity of these adsorptions are reflected by the free Gibbs energies of -22.1 ± 0.4 and -21.5 ± 0.2 kJ mol -1 , respectively, found for these systems. This new adsorbent derived from a natural polysaccharide is as efficient as activated carbon. However 97% of the bonded dye can be eluted by sodium chloride solution, while this same operation elutes only 42% from carbon. Chitosan is efficient in dye removal with the additional advantage of being cheap, non-toxic, biocompatible and biodegradable.Keywords: chitosan; succinic anhydride; methylene blue. INTRODUÇÃOOs polissacarídeos denominados β(1→4)2-acetamida-2-desoxi-D-glicopiranose e β(1→4)2-amino-2-desoxi-D-glicopiranose são conhecidos pelas denominações quitina e quitosana, respectivamente. São biopolímeros interligados por ligações β-glicosídicas, sendo que em ambos os tipos de estruturas não há predominância de quaisquer espécies monoméricas. Assim, ambas as formas coexistem na natureza em uma estrutura polimérica, com grau parcial de desacetilação 1 , constituindo um copolímero. A quitina nativa possui em torno de 10% de grupos aminos livres 2 , enquanto que a forma desacetilada apresenta, em média, um teor desses grupos 1,2 não superior a 97%.Quanto à natureza estrutural desses materiais, tem-se conhecimento de que a quitina pode se apresentar sob as formas α, β e γ. Entretanto, a última é ainda pouco estudada, provavelmente por conter percentuais predominantes das formas α e β na sua constituição. Tanto a quitina natural como a quitosana apresentam alto grau de associação com proteínas, formando as glicoproteínas, com percentual que varia de 20 a 50% nos artrópodes 3 . A quitina faz parte da constituição da estrutura material e protetora dos insetos, animais marinhos e microrganismos celulares. Em processo laboratorial, a quitina é obtida a partir da abertura de anel do grupo exazolina de um derivado de açúcar ou por biossíntese, a partir da glicose em processo enzimático 3 . Um grande número de modificações químicas através de rotas homogênea e heterogênea pode ser realizado no anel glicopiranosídeo d...

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“…La adsorción del anión dicromato en el Cu-quitosano puede deberse a la fuerte atracción electrostática entre dicromato y el Cu enlazado a los grupos amino (NH2) en el quitosano; donde el principal mecanismo de interacción para el Cu puede ser por quelación (Vieira et al, 2007). Rhazi et al (2002) propuso la siguiente estructura para el complejo Cu-quitosano: Vol. 26, No.…”

Section: Estudio Comparativo De La Adsorción De Cr(vi) En Quitosano Yunclassified

“…02, pp. 56-68/Diciembre 2013 Fig.1 Estructura propuesta para el complejo Cuquitosano (Rhazi et al, 2002) Donde los grupos hidroxilos (OH-) pueden ser sustituidos por un anión dicromato Cr2O72-, proponiéndose la siguiente estructura:…”

Section: Estudio Comparativo De La Adsorción De Cr(vi) En Quitosano Yunclassified

Estudio del equilibrio y cinética de adsorción de Cd(II), Ni(II) y Cr(VI) usando Quitosano y Quitosano modificado con cobre

Castro

Cruz

Betanco

et al. 2014

Nexo Revista Científica

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RESUMENEn este trabajo, se estudió el equilibrio y la cinética de adsorción de Cd(II), Ni(II) en quitosano y Cr(VI) en quitosano modificado con cobre. Para ello, soluciones de iones metálicos a diferentes concentraciones, fueron puestas en contacto con el adsorbente y se agitaron por un período de 3 -4 h. Al final del proceso, las muestras fueron analizadas en un espectrómetro de absorción atómica. Los datos experimentales del equilibrio de adsorción de los iones metálicos fueron evaluados aplicando las isotermas de Langmuir y Freundlich; mientras los datos cinéticos fueron evaluados utilizando los modelos cinéticos de pseudo-primer orden y pseudo-segundo orden. Los resultados del proceso demostraron que los iones fueron eficazmente adsorbidos por el quitosano (Cd y Ni) y por el Cuquitosano (Cr). Además, se comprobó que los datos experimentales del equilibrio de adsorción de Cr(VI) y Ni(II) se ajustan al modelo de Langmuir; mientras que los datos experimentales del Cd(II) fueron mejor ajustados por el modelo de Freundlich. Mediante el uso de la isoterma de Langmuir se determinó la capacidad máxima de adsorción de cromo (29.7 mg/g Cu-quitosano), cadmio (102.0 mg/g quitosano) y níquel (83.31 mg/g quitosano). Los resultados de la cinética de adsorción de los iones metálicos mostraron que los datos experimentales fueron mejor ajustados por el modelo de pseudo-segundo orden; es decir, el paso limitante en la velocidad es la reacción de adsorción y no la transferencia de masa.Palabras claves: isotermas de adsorción; cinética de adsorción; modelos cinéticos; metales pesados; quitosano; Cu-quitosano ABSTRACTIn this paper, the equilibrium and adsorption kinetics of Cr(VI), Cd(II) and Ni(II) onto Chitosan and Cu-chitosan was studied. Metal ion solutions at different initial concentration were put in contact with chitosan and Cu-chitosan and the mixture was agitated by 3 -4 h. Afterwards, the samples were analyzed by atomic absorption spectroscopy. The experimental data of adsorption equilibrium were evaluated by application of Langmuir and Freundlich isotherms; while the kinetics experimental data were evaluated using kinetic models of pseudo-first order and pseudo-second order. The results showed that the metallic ions were effectively adsorbed by the chitosan (Cd and Ni) and Cuchitosan (Cr). Besides, it was found that the experimental data of adsorption equilibrium of Cr(VI) and Ni(II) fit the Langmuir model, while the equilibrium adsorption data of Cd(II) were better fitted by Freundlich model. The maximum adsorption capacity of chromium (29.7 mg/g Cu-chitosan), cadmium (102.0 mg/g chitosan) and nickel (83.31 mg/g chitosan) was determined using the Langmuir model. The results of adsorption kinetics of the metallic ions showed that the experimental data were better adjusted by pseudo-second order model. Therefore, the ratelimiting step is the adsorption reaction and not mass transfer processes.

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Contribution to the study of the complexation of copper by chitosan and oligomers

Cited by 224 publications

References 34 publications

Interaction of carboxymethylchitosan and heavy metals in cement media

Interaction of carboxymethylchitosan and heavy metals in cement media

O emprego de quitosana quimicamente modificada com anidrido succínico na adsorção de azul de metileno

Estudio del equilibrio y cinética de adsorción de Cd(II), Ni(II) y Cr(VI) usando Quitosano y Quitosano modificado con cobre

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