Abstract
Interfacial Fe(II)-Fe(III) electron transfer and atom exchange in smectites; effect of smectite properties
Mineralogical magazine, Vol.76(6), p.2164
Goldschmidt 2012
2012
Abstract
Heterogeneous reactions between aqueous Fe(II) and Fe(III) oxides have extensively been studied, leading to a new conceptual framework which includes electron transfer between aqueous Fe(II) and structural Fe(III), bulk electron conduction, and Fe(II)-Fe(III) atom exchange. A recent study showed that interfacial electron transfer between aqueous Fe(II) and structural Fe(III) also occurred in one clay mineral. Whether this observation can be generalized for all clay minerals and whether similar processes as observed for the heterogeneous redox reaction in Fe(III) oxides are also crucial for clay mineral redox reactions is unclear. Studies on chemical reduction of structural Fe in smectites showed that the type of reductant as well as smectite structural properties determined the extent of Fe reduction and the resulting structural Fe(II) entities. Thus, we investigated well-characterized smectites differing in structural Fe content, location of structural Fe (octahedral vs. tetrahedral), and location of excess charge (octahedral vs. tetrahedral) for their reaction with aqueous Fe(II), a reductant abundant in natural anaerobic environments. Stable isotope specific Mossbauer spectroscopy was used to determine the extent of reduction of structural Fe in smectites after exposure to aqueous (super 56) Fe(II), which is invisible in Mossbauer spectra. Experiments with aqueous Fe(II) enriched in (super 57) Fe were carried out to determine the exchange of stable Fe isotopes between aqueous Fe(II) and structural Fe(III) in smectites. Different pools of Fe(II) and Fe(III) were investigated by sequential extraction procedures and solid reaction products were characterized with X-ray diffraction and electron-based microscopic methods.
Details
- Title: Subtitle
- Interfacial Fe(II)-Fe(III) electron transfer and atom exchange in smectites; effect of smectite properties
- Creators
- Anke Neumann - University of IowaMichelle M Scherer
- Resource Type
- Abstract
- Publication Details
- Mineralogical magazine, Vol.76(6), p.2164
- Conference
- Goldschmidt 2012
- Publisher
- Mineralogical Society
- ISSN
- 0026-461X
- eISSN
- 1471-8022
- Alternative title
- Goldschmidt 2012 abstract volume
- Language
- English
- Date published
- 2012
- Academic Unit
- Civil and Environmental Engineering
- Record Identifier
- 9984202247502771
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