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Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron (Oxy)Hydroxides, Trace Elements, and Bacteria
Published on: December 19, 2017
Iron-monosulfide oxidation in natural sediments: resolving microbially mediated S transformations using XANES,
E D Burton1, R T Bush, L A Sullivan
1A Centre for Acid Sulfate Soil Research, Southern Cross GeoScience, Southern Cross University, Lismore, NSW 2480, Australia. ed.burton@scu.edu.au
Environmental Science & Technology
|June 19, 2009
Summary
Iron-monosulfide (FeS) rapidly oxidizes abiotically to elemental sulfur (S8(0)) in sediments. Microbial activity then transforms this elemental sulfur into sulfate (SO4(2-)).
Area of Science:
- Geochemistry
- Environmental Science
- Microbiology
Background:
- Sediments receiving acid-sulfate soil drainage are rich in iron-monosulfide (FeS).
- Understanding FeS oxidation and sulfur transformations is crucial for environmental remediation.
Purpose of the Study:
- To investigate the oxidation of iron-monosulfide and associated sulfur transformations in natural sediments.
- To determine the roles of abiotic and biotic processes in these transformations.
Main Methods:
- Selective extractions
- Transmission electron microscopy
- Sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy
Main Results:
- Iron-monosulfide, primarily nanocrystalline mackinawite, rapidly oxidized abiotically.
- Elemental sulfur (S8(0)) was identified as a key intermediate oxidation product.
- Microbial activity was essential for the subsequent oxidation of elemental sulfur to sulfate (SO4(2-)).
Conclusions:
- The abiotic oxidation of mackinawite is rapid and not microbially mediated.
- Elemental sulfur is a significant intermediate in sulfur cycling within these sediments.
- Microbial processes are critical for the complete oxidation of sulfur compounds to sulfate.
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