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metadata.artigo.dc.title: Nanostructured oxide stabilized by chitosan: hybrid composite as an adsorbent for the removal of chromium (VI)
metadata.artigo.dc.creator: Chagas, Pricila Maria Batista
Carvalho, Lucas Bragança de
Caetano, Aline Aparecida
Nogueira, Francisco Guilherme Esteves
Corrêa, Angelita Duarte
Guimarães, Iara do Rosário
metadata.artigo.dc.subject: Hybrid biocomposite
Iron oxide
Hexavalent chromium removal
Reduction-chelation mechanism
Biocompósito híbrido
Óxido de ferro
Remoção de cromo hexavalente
Mecanismo de quelação de redução
metadata.artigo.dc.publisher: Elsevier Feb-2018
metadata.artigo.dc.identifier.citation: CHAGAS, P. M. B. et al. Nanostructured oxide stabilized by chitosan: hybrid composite as an adsorbent for the removal of chromium (VI). Journal of Environmental Chemical Engineering, [S. l.], v. 6, n. 1, p. 1008-1019, Feb. 2018.
metadata.artigo.dc.description.abstract: The surface of iron oxides can be modified by treatments using organic components, which is an alternative for the production of new materials. Chitosan (CT) is a polymer that has been widely used as a protective and stabilizing agent, which can functionalize and improve adsorbent properties of iron oxides. In this study, the synthesis of chitosan-stabilized nanostructured iron oxide was carried out for application and the optimization of Cr(VI) removal. The material was synthesized by the direct incorporation of Fe(II) into the chitosan gel, producing CT-Fe beads. The chemical, morphological and structural characterizations of the materials were performed using SEM, XRD, FTIR, TGA and DSC. The magnetic iron oxide produced together with chitosan was identified as magnetite (Fe3O4). In the formation of the CT-Fe composite, chitosan chains became less ordered, providing the formation of low-crystalline magnetic iron oxide capable of increasing the adsorption capacity. CT-Fe composite showed higher capacity for the removal of Cr(VI), relative when compared to pure magnetite. Kinetic studies showed that chromium adsorption follows the pseudo-second order model, indicating chemical adsorption. The removal of Cr(VI) was pH-dependent and the highest removal was obtained in acid medium, in which the groups present on the surface of the materials are fully protonated, facilitating the electrostatic attraction of HCrO4−. Furthermore, the reduction of Cr(VI) by Fe(II) can cause Cr(III) to return to the aqueous medium and being readsorbed. The CT-Fe composite has promising adsorption capacity with remarkable reuse for the removal of chromium from solution.
metadata.artigo.dc.language: en_US
Appears in Collections:DQI - Artigos publicados em periódicos

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