Effect of chromium speciation on its sorption mechanism onto grape stalks entrapped into alginate beads
dc.contributor.author
dc.date.accessioned
2017-06-02T10:11:56Z
dc.date.available
2017-06-02T10:11:56Z
dc.date.issued
2017-02-01
dc.identifier.issn
1878-5352
dc.identifier.uri
dc.description.abstract
Sorption of Cr(III) and Cr(VI) ions onto 2% grape stalk (GS) powder entrapped in a biopolymeric gel matrix of calcium alginate (CA) has been investigated and a mechanism for the retention of both, Cr(VI) and Cr(III) is proposed. Protons were found to be consumed in Cr(VI) sorption/reduction and to compete with Cr(III) for the sorbent active sites. Isotherm equilibrium was modelled according to Langmuir equation: maximum capacity was found to be 6.4 and 3.6 mg g−1 for Cr(III) and Cr(VI), respectively. The important Ca2+ release observed when Cr(III) is sorbed indicates that ion exchange is the main mechanism involved at concentrations lower than 200 mg L−1 while other mechanisms such as microprecipitation or coordination might take place for higher initial concentrations. In the case of Cr(VI), the sorption mechanism is based on the reduction to Cr(III) promoted by both protons and the functional groups on the GS surface; this reduction-formed Cr(III) is retained by the alginate gel matrix and by microprecipitation onto the surface of GS particles. ESR and SEM-EDX were used to identify chromium species sorbed on the solid phase. Results from this study suggest that GS entrapped in CA gel beads is an effective sorbent for both, Cr(III) and Cr(VI) removal from aqueous solutions
dc.format.mimetype
application/pdf
dc.language.iso
eng
dc.publisher
Elsevier
dc.relation.isformatof
Reproducció digital del document publicat a: http://dx.doi.org/10.1016/j.arabjc.2013.03.011
dc.relation.ispartof
Arabian Journal of Chemistry, 2017, vol. 10, suplement 1, p. S1293-S1302
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Articles publicats (D-EQATA)
dc.rights
Attribution-NonCommercial-NoDerivs 3.0 Spain
dc.rights.uri
dc.title
Effect of chromium speciation on its sorption mechanism onto grape stalks entrapped into alginate beads
dc.type
info:eu-repo/semantics/article
dc.rights.accessRights
info:eu-repo/semantics/openAccess
dc.embargo.terms
Cap
dc.type.version
info:eu-repo/semantics/publishedVersion
dc.identifier.doi
dc.identifier.idgrec
018069