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Journal of Chemistry
Volume 2013, Article ID 751696, 9 pages
Research Article

Adsorption Behaviour of La(III) and Eu(III) Ions from Aqueous Solutions by Hydroxyapatite: Kinetic, Isotherm, and Thermodynamic Studies

1Departamento de Química, Instituto Nacional de Investigaciones Nucleares, P.O. Box 18-1027, Colonia Escandón, Delegación Miguel Hidalgo, 11801 Mexico City, DF, Mexico
2Instituto Tecnológico de Zitácuaro, Ex Hacienda de Manzanillos S/N. Colonia Mojonera, 61500 Zitácuaro, Michoacán, Mexico

Received 20 June 2012; Accepted 29 August 2012

Academic Editor: Patricia Valentao

Copyright © 2013 F. Granados-Correa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The hydroxyapatite was successfully synthesized, characterized, and used as an alternative low-cost adsorbent material to study the adsorption behavior of La(III) and Eu(III) ions from nitrate aqueous solutions as a function of contact time, initial metal ion concentration, pH, and temperature by using a bath technique. The kinetic data correspond very well to the pseudo-second-order equation, and in both cases the uptake was affected by intraparticle diffusion. Isotherm adsorption data were well fitted by the Freundlich model equation with , indicating a multilayer and cooperative-type adsorption. Thermodynamic parameters for the adsorption systems were determinated at 293, 303, 313, and 323 K. These parameters show that adsorptions of La(III) and Eu(III) ions on hydroxyapatite are endothermic and spontaneous processes. The adsorption was found to follow the order Eu(III) > La(III) and is dependent on ion concentration, pH, and temperature.