Journal article
The Role of Defects in Fe(II)–Goethite Electron Transfer
Environmental science & technology, Vol.52(5), pp.2751-2759
03/06/2018
DOI: 10.1021/acs.est.7b05772
PMID: 29405066
Abstract
Despite substantial experimental evidence for Fe(II)–Fe(III) oxide electron transfer, computational chemistry calculations suggest that oxidation of sorbed Fe(II) by goethite is kinetically inhibited on structurally perfect surfaces. We used a combination of 57Fe Mössbauer spectroscopy, synchrotron X-ray absorption and magnetic circular dichroism (XAS/XMCD) spectroscopies to investigate whether Fe(II)–goethite electron transfer is influenced by defects. Specifically, Fe L-edge and O K-edge XAS indicates that the outermost few Angstroms of goethite synthesized by low temperature Fe(III) hydrolysis is iron deficient relative to oxygen, suggesting the presence of defects from Fe vacancies. This nonstoichiometric goethite undergoes facile Fe(II)–Fe(III) oxide electron transfer, depositing additional goethite consistent with experimental precedent. Hydrothermal treatment of this goethite, however, appears to remove defects, decrease the amount of Fe(II) oxidation, and change the composition of the oxidation product. When hydrothermally treated goethite was ground, surface defect characteristics as well as the extent of electron transfer were largely restored. Our findings suggest that surface defects play a commanding role in Fe(II)–goethite redox interaction, as predicted by computational chemistry. Moreover, it suggests that, in the environment, the extent of this interaction will vary depending on diagenetic history, local redox conditions, as well as being subject to regeneration via seasonal fluctuations.
Details
- Title: Subtitle
- The Role of Defects in Fe(II)–Goethite Electron Transfer
- Creators
- Luiza Notini - University of IowaDrew E Latta - University of IowaAnke Neumann - Newcastle UniversityCarolyn I Pearce - Pacific Northwest National LaboratoryMichel Sassi - Pacific Northwest National LaboratoryAlpha T N’Diaye - Lawrence Berkeley National LaboratoryKevin M Rosso - Pacific Northwest National LaboratoryMichelle M Scherer - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Environmental science & technology, Vol.52(5), pp.2751-2759
- Publisher
- American Chemical Society
- DOI
- 10.1021/acs.est.7b05772
- PMID
- 29405066
- ISSN
- 0013-936X
- eISSN
- 1520-5851
- Grant note
- DOI: 10.13039/100000165, name: Division of Chemistry, award: CHE-1347848; DOI: 10.13039/100006151, name: Basic Energy Sciences, award: DE-AC02-05CH11231; DOI: 10.13039/100000993, name: Battelle, award: DE-AC06-76RLO-1830
- Language
- English
- Date published
- 03/06/2018
- Academic Unit
- Civil and Environmental Engineering; IIHR--Hydroscience and Engineering
- Record Identifier
- 9984197076802771
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