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Cd(II) speciation in alginate gels

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dc.contributor.authorDavis, T. A.
dc.contributor.authorKalis, E. J. J.
dc.contributor.authorPinheiro, J. P.
dc.contributor.authorTown, R. M.
dc.contributor.authorVan Leeuwen, H. P.
dc.date.accessioned2013-12-03T15:04:18Z
dc.date.available2013-12-03T15:04:18Z
dc.date.issued2008
dc.date.updated2013-11-26T16:27:05Z
dc.description.abstractPolysaccharides, such as those occurring in cell walls and biofilms, play an important role in metal speciation in natural aqueous systems. This work describes the speciation of Cd(II) in alginate gels chosen as a model system for biogels. The gels are formed by bridging calcium ions at junction zones present along adjacent homopolymeric guluronic acid chain sequences. The free Cd2+ concentration in the gel phase is measured by a novel in situ microelectrode voltammetric technique that monitors the electroactive probe cation Cd2+ by its reduction at a Au-amalgam microelectrode. In situ voltammetric measurement, coupled with total Ca(II) and Cd(II) determinations, as well as potentiometric titration, permits the full reconstruction of the charging environment and the cation binding for the gel phase. Three independent combinations of measuring and modeling the charged gel layer thereby permit accurate prediction of the Donnan potential, ΨD, and the Donnan enrichment coefficient, ΠD. At an ionic strength of 10 mM, Donnan potentials in the gel ranged from approximately −10 to −20 mV, corresponding to an enhancement in the level of free Cd2+ ions in the gel phase relative to the bulk solution by a factor of approximately 3. In contrast, the total level of Cd(II) was found to be enhanced by a factor of approximately 60, resulting predominantly from the specific binding of the Cd by the uronic acids of the alginate gel. These results emphasize that large differences in Cd(II) speciation can arise due to the combination of specific and electrostatic modes of binding. The results of this speciation analysis, for charged biological gels, have important consequences for mechanistic interpretation of metal biouptake processes involved in complex media.por
dc.identifier.citationDavis, T. A.; Kalis, E. J. J.; Pinheiro, J. P.; Town, R. M.; Van Leeuwen, H. P. Cd(II) speciation in alginate gels, Environmental Science and Technology, 42, 19, 7242-72, 2008.por
dc.identifier.doihttp://dx.doi.org/10.1021/es801068c
dc.identifier.issn0013-936X
dc.identifier.otherAUT: JPI01020;
dc.identifier.urihttp://hdl.handle.net/10400.1/3214
dc.language.isoengpor
dc.peerreviewedyespor
dc.publisherAmerican Chemical Societypor
dc.titleCd(II) speciation in alginate gelspor
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage7247por
oaire.citation.issue19por
oaire.citation.startPage7242por
oaire.citation.titleEnvironmental Science and Technologypor
oaire.citation.volume42por
person.familyNamePinheiro
person.givenNameJosé Paulo
person.identifier.orcid0000-0001-7925-9733
person.identifier.ridE-8402-2013
person.identifier.scopus-author-id35838299700
rcaap.rightsrestrictedAccesspor
rcaap.typearticlepor
relation.isAuthorOfPublication5caedbac-d2b5-4a86-91a7-083bf83edda3
relation.isAuthorOfPublication.latestForDiscovery5caedbac-d2b5-4a86-91a7-083bf83edda3

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