Publication:
Reduction of organically complexed ferric iron by superoxide in a simulated natural water

dc.contributor.author Rose, Andrew en_US
dc.contributor.author Waite, David en_US
dc.date.accessioned 2021-11-25T14:16:27Z
dc.date.available 2021-11-25T14:16:27Z
dc.date.issued 2005 en_US
dc.description.abstract Superoxide (and potentially its conjugate acid hydroperoxyl) is unique among the reactive oxygen species in that its standard redox potential in circumneutral natural waters potentially allows it to reduce ferric iron to the more soluble ferrous state. Here we have observed the superoxide/hydroperoxyl-mediated reduction of ferric complexes with a variety of synthetic organic ligands and several complexes with natural organic matter (NOM), as well as freshly precipitated amorphous ferric oxyhydroxide, in bicarbonate buffered solutions at pH 8.1. From measurements of superoxide decay in the presence of the complexes, we calculated second-order rate constants for superoxide/hydroperoxyl-mediated reduction that vary from (9.3 0.2) x 10(3) M-1 s(-1) for the complex between Fe(III) and desferrioxamine B up to (1.9 +/- 0.2) x 10(5) M-1 s-1 for Fe(III)-salicylate and (2.3 +/- 0.1) x 10(5) M-1 s(-1) for one of the Fe(III)-NOM complexes. We also verified that ferrous iron was produced from superoxide/hydroperoxyl-mediated Fe(III) reduction using ferrozine to trap free Fe(II). Low yields of the ferrozine complex when compared to the measured rates of superoxide decay suggest that ferric complexes are reduced directly to corresponding ferrous complexes, with much of the ferrous complex reoxidizing before it is able to release free ferrous iron. This is an important consideration for microorganisms, as the kinetics of trace metal uptake is typically governed by free ion activity. en_US
dc.identifier.uri http://hdl.handle.net/1959.4/42323
dc.language English
dc.language.iso EN en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri https://creativecommons.org/licenses/by-nc-nd/3.0/au/ en_US
dc.source Legacy MARC en_US
dc.title Reduction of organically complexed ferric iron by superoxide in a simulated natural water en_US
dc.type Journal Article en
dcterms.accessRights metadata only access
dspace.entity.type Publication en_US
unsw.accessRights.uri http://purl.org/coar/access_right/c_14cb
unsw.relation.faculty Engineering
unsw.relation.ispartofissue 8 en_US
unsw.relation.ispartofjournal Environmental Science & Technology en_US
unsw.relation.ispartofpagefrompageto 2645-2650 en_US
unsw.relation.ispartofvolume 39 en_US
unsw.relation.originalPublicationAffiliation Rose, Andrew, Civil & Environmental Engineering, Faculty of Engineering, UNSW en_US
unsw.relation.originalPublicationAffiliation Waite, David, Civil & Environmental Engineering, Faculty of Engineering, UNSW en_US
unsw.relation.school School of Civil and Environmental Engineering *
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