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Journal of Chemistry
Volume 2016 (2016), Article ID 7296858, 13 pages
http://dx.doi.org/10.1155/2016/7296858
Research Article

Removal of Fluoride from Aqueous Solutions Using Chitosan Cryogels

1Tecnológico Nacional de México/Instituto Tecnológico de Toluca, Avenida Tecnológico S/N, Colonia Agrícola Bella Vista, 52149 Metepec, MEX, Mexico
2Dirección de Investigación Tecnológica, Instituto Nacional de Investigaciones Nucleares (ININ), Carretera México-Toluca S/N, La Marquesa, 52750 Ocoyoacac, MEX, Mexico

Received 22 July 2016; Accepted 21 November 2016

Academic Editor: Julie J. M. Mesa

Copyright © 2016 Anete Jessica Arcos-Arévalo 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.

Abstract

In this study, crosslinked chitosan cryogels (QE) and chitosan’s cryogels modified with iron (QEFe) were synthesized. They were characterized by BET, PZC, FTIR, and XPS spectroscopies. Results show a specific surface area of 36.67 and 29.17 m2g−1 and 7.0 and 6.1 of PZC for the cryogels QE and QEFe, respectively. FTIR results show the characteristic bands of amino and hydroxyl groups, while in the XPS analysis, interactions between iron and oxygen with fluorine were observed. The removal of fluoride at temperatures of 303, 313, and 323 K in cryogels was tested. The Ho model is the best fit for the experimental data, suggesting that there is a chemisorption process involved in the removal of fluoride. The Langmuir-Freundlich model is the best to represent the behavior of the cryogels, and it is used to sorbents with heterogeneous surfaces. A maximum fluoride adsorption capacity of 280 and 295 mg F/g for QE and QEFe, respectively, at 303 K was obtained, showing that the removal of fluoride is favored by the iron incorporated in the polymer matrix of the cryogels. The thermodynamic parameters were obtained for both cryogels, where the values of and indicate that both systems are endothermic and nonspontaneous.