Journal article
FeIIaq–FeIIIoxide electron transfer and Fe exchange: effect of organic carbon
Environmental chemistry, Vol.12(1), pp.52-63
2015
DOI: 10.1071/EN14035
Abstract
Environmental context Concerns about carbon-driven climate change make it critical to better understand how carbon interacts with soils. We examined whether carbon compounds commonly found in soils affect the behaviour of soil iron minerals, and found that iron minerals remain dynamic and mix with the surrounding water, despite the presence of carbon in the water. Our findings suggest that both carbon and trace elements in the minerals may be more mobile and less stable than we previously thought. Abstract The close association of organic carbon and Fe oxides has been recognised for decades and recently interest in the role of Fe oxides in organic C sequestration has increased. Here we explore the effect of natural organic C on electron transfer and exchange of aqueous FeII and Fe in the bulk structure of goethite and magnetite. Using 57Fe isotope experiments coupled with 57Fe Mössbauer spectroscopy it is found that electron transfer occurs between aqueous FeII and structural FeIII in both goethite and magnetite in the presence of most organic C compounds, including natural organic matter (NOM), extracellular polysaccharides (EPS), and cell materials. Only a long-chain (39-C) phospholipid containing organic C significantly inhibited electron transfer. Despite evidence for FeII–FeIIIoxide electron transfer in the presence of NOM, exchange of Fe between the aqueous phase and bulk Fe was less than observed in the absence of NOM. Our findings suggest that electron transfer between aqueous FeII and bulk structural Fe in goethite and magnetite is a robust process likely to occur in a variety of organic-rich biogeochemical environments but that Fe exchange may be inhibited by the presence of some C compounds.
Details
- Title: Subtitle
- FeIIaq–FeIIIoxide electron transfer and Fe exchange: effect of organic carbon
- Creators
- Timothy Pasakarnis - University of IowaMichael L McCormick - Hamilton CollegeGene F Parkin - University of IowaAaron ThompsonMichelle M Scherer - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Environmental chemistry, Vol.12(1), pp.52-63
- DOI
- 10.1071/EN14035
- ISSN
- 1448-2517
- eISSN
- 1449-8979
- Language
- English
- Date published
- 2015
- Academic Unit
- Civil and Environmental Engineering
- Record Identifier
- 9984197410502771
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