- Title
- Iron-monosulfide oxidation in natural sediments : Resolving microbially mediated S transformations using XANES, electron microscopy, and selective extractions
- Creator
- Burton, Edward; Bush, Richard; Sullivan, Leigh; Hocking, Rosalie; Mitchell, David; Johnston, Scott; Fitzpatrick, Rob W.; Raven, Mark; McClure, Stuart; Jang, Lingyun
- Date
- 2009
- Type
- Text; Journal article
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/99502
- Identifier
- vital:10374
- Identifier
-
https://doi.org/10.1021/es8036548
- Identifier
- ISSN:0013-936X
- Abstract
- Iron-monosulfide oxidation and associated S transformations in a natural sediment were examined by combining selective extractions, electron microscopy and S K-edge X-ray absorption near-edge structure (XANES) spectroscopy. The sediment examined in this study was collected from a waterway receiving acid-sulfate soil drainage. It contained a high acid-volatile sulfide content (1031 μ mol g-1), reflecting an abundance of iron-monosulfide. The iron-monosulfide speciation in the initial sediment sample was dominated by nanocrystalline mackinawite (tetragonal FeS). At near-neutral pH and an O 2 partial pressure of ∼0.2 atm, the mackinawite was found to oxidize rapidly, with a half-time of 29 ± 2 min. This oxidation rate did not differ significantly (P < 0.05) between abiotic versus biotic conditions, demonstrating that oxidation of nanocrystalline mackinawite was not microbially mediated. The extraction results suggested that elemental S (S0 8) was a key intermediate S oxidation product. Transmission electron microscopy showed the S0 8 to be amorphous nanoglobules, 100-200 nm in diameter. The quantitative importance of S0 8 was confirmed by linear combination XANES spectroscopy, after accounting for the inherent effect of the nanoscale S0 8 particle-size on the corresponding XANES spectrum. Both the selective extraction and XANES data showed that oxidation of S0 8 SO4 2- was madiated by microbial activity. In addition to directly revealing important S transformations, the XANES results support the accuracy of the selective extraction scheme employed here. © 2009 American Chemical Society.
- Publisher
- ACS Publications
- Relation
- Environmental Science and Technology Vol. 43, no. 9 (2009), p. 3128-3134
- Rights
- Copyright © 2009 American Chemical Society.
- Rights
- This metadata is freely available under a CCO license
- Subject
- MD Multidisciplinary; Acid-volatile sulfide; Biotic conditions; Inherent effect; Linear combinations; Mackinawite; Microbial activities; Monosulfide; Nano scale; Nanocrystalline; Nanoglobules; Natural sediments; Near-neutral pH; Oxidation products; Oxidation rates; S-transformation; Sediment samples; Selective extraction; Sulfate soils; XANES; XANES spectra; XANES spectroscopy
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