Adsorption isotherms and thermochemical data of FD&C Red n° 40 binding by Chitosan

Brazilian Journal of Chemical Engineering

J. S. Piccin¹  G. L. Dotto¹  L. A. A. Pinto¹ 

[1] ,Federal University of Rio Grande School of Chemistry and Food Unit Operation laboratoryRio Grande RS ,Brazil

关键词: Dye adsorption;    Chitosan;    Isotherm models;   

DOI  :  10.1590/S0104-66322011000200014

来源: SciELO

【 摘 要 】

Chitosan is a natural polymer that has been employed in dye adsorption. In this work, adsorption and thermodynamic data for the interaction of FD&C Red n° 40 food dye with chitosan in aqueous solutions were investigated. The equilibrium adsorption isotherms were determined by the batch method, from 298 to 338 K. Adsorption data were adjusted to five isotherm models: Langmuir, Freundlich, Redlich-Peterson, Temkin and Dubinin-Radushkevich, in order to determine which presented the best adjustment to the experimental data. Error analysis showed that the Langmuir isotherm model was the most appropriate for fitting the experimental data, with a maximum monolayer adsorption of 3065.8 µmol g-1 at 308 K. Negative enthalpy (-112.7 kJ mol-1), entropy (-0.338 kJ mol-1 K-1) and Gibbs free energy (-15.6 to 1.0 kJ mol-1) values demonstrated that the adsorption process is exothermic, spontaneous, favorable, and that randomness of the system decreases during the adsorption process.

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