Adsorption Equilibria of Cu2+, Zn2+, and Cd2+ on EDTA-Functionalized Silica Spheres

Autor:	Allen L. Barros, Diego de Quadros Melo, Ronaldo Ferreira do Nascimento, Juliene Tomé Oliveira, Giselle Santiago Cabral Raulino, Vicente de Oliveira Sousa Neto, Elisane Longuinotti, Elis C.C. Gomes
Rok vydání:	2013
Předmět:	Langmuir Aqueous solution Chemistry General Chemical Engineering Metal ions in aqueous solution Inorganic chemistry Langmuir adsorption model Ethylenediaminetetraacetic acid General Chemistry symbols.namesake chemistry.chemical_compound Adsorption Chemisorption symbols Freundlich equation
Zdroj:	Journal of Chemical & Engineering Data. 58:798-806
ISSN:	1520-5134 0021-9568
DOI:	10.1021/je3013364
Popis:	Ethylenediaminetetraacetic acid (EDTA) functionalized silica spheres were used to remove metal ions from aqueous solutions. The adsorption kinetics of Cu2+, Zn2+, and Cd2+ (60 mg·L–1, pH 5.5) were fitted to the pseudosecond order model. Adsorption equilibria were reached within 20 min, indicating that chemisorption may be the limiting step in the adsorption process. Adsorption isotherms were analyzed with nonlinear models by considering the ERRSQ error function and the determination coefficient R2. The data with monoion solutions (10 mg·L–1 to 300 mg·L–1) were tested with Langmuir, Freundlich, and Redlich–Peterson isotherm models. The best fit was found with the Langmuir model, and maximum adsorption capacities followed the order: Cu2+ > Zn2+ > Cd2+. Breakthrough curves were obtained using filled columns. The adsorbed ions were quantitatively recovered on elution with hydrogen chloride (0.10 M). After three adsorption–recovery cycles, the metal ions could still be recovered almost quantitatively, which de...
Databáze:	OpenAIRE
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