Journal article
Superoxide mediated reduction of organically complexed Iron(III): comparison of non-dissociative and dissociative reduction pathways
Environmental Science & Technology, Vol.41(9), pp.3205-3212
2007
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Source: InCites
Abstract
<p>We have investigated the mechanism of reduction of organically complexed iron(III) in the presence of superoxide, the one-electron reduced form of dioxygen that is produced in natural waters by thermal, photochemical, and biological pathways. Experimental results show that reduction of organically complexed iron(III) by superoxide may occur by either (or, in some instances, both) reaction of superoxide with inorganic iron(III) after its dissociation from the complex (dissociative reduction) or by direct reaction of superoxide with the complex (non-dissociative reduction). In the presence of low concentrations of ligands such as citrate and sulfosalicylate that bind iron(III) relatively weakly and result in complexes with high dissociation rate constants (<em>k</em>d > 1 × 10-4 s-1), a dissociative reduction pathway dominates. However, in the presence of strong ligands or high concentrations of weak ligands, only non-dissociative reduction of complexed iron(III) occurs. The relative contribution of each pathway has major implications for the lability and hence potential bioavailablity of iron in natural waters. The simple kinetic model developed here can be used to correctly predict the superoxide-mediated formation rates of iron(II) in natural systems.</p>
Details
- Title
- Superoxide mediated reduction of organically complexed Iron(III): comparison of non-dissociative and dissociative reduction pathways
- Creators
- Shikha Garg - University of New South WalesAndrew L Rose - University of New South WalesT David Waite - University of New South Wales
- Publication Details
- Environmental Science & Technology, Vol.41(9), pp.3205-3212
- Identifiers
- 1263; 991012820300702368
- Academic Unit
- Faculty of Science and Engineering; Southern Cross GeoScience; Engineering
- Resource Type
- Journal article