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Reduction of Sb(V) by coupled biotic-abiotic processes under sulfidogenic conditions.

Authors
  • Johnson, Clayton R1
  • Antonopoulos, Dionysios A1
  • Boyanov, Maxim I1, 2
  • Flynn, Theodore M1
  • Koval, Jason C1
  • Kemner, Kenneth M1
  • O'Loughlin, Edward J1
  • 1 Biosciences Division, Argonne National Laboratory, Lemont, IL 60439-4843.
  • 2 Bulgarian Academy of Sciences, Institute of Chemical Engineering, Sofia, 1113, Bulgaria. , (Bulgaria)
Type
Published Article
Journal
Heliyon
Publisher
Elsevier
Publication Date
Feb 01, 2021
Volume
7
Issue
2
Identifiers
DOI: 10.1016/j.heliyon.2021.e06275
PMID: 33681496
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

Increasing use and mining of antimony (Sb) has resulted in greater concern involving its fate and transport in the environment. Antimony(V) and (III) are the two most environmentally relevant oxidation states, but little is known about the redox transitions between the two in natural systems. To better understand the behavior of antimony in anoxic environments, the redox transformations of Sb(V) were studied in biotic and abiotic reactors. The biotic reactors contained Sb(V) (2 mM as KSb(OH)6), ferrihydrite (50 mM Fe(III)), sulfate (10 mM), and lactate (10 mM), that were inoculated with sediment from a wetland. In the abiotic reactors, The interaction of Sb(V) with green rust, magnetite, siderite, vivianite or mackinawite was examined under abiotic conditions. Changes in the concentrations of Sb, Fe(II), sulfate, and lactate, as well as the microbial community composition were monitored over time. Lactate was rapidly fermented to acetate and propionate in the bioreactors, with the latter serving as the primary electron donor for dissimilatory sulfate reduction (DSR). The reduction of ferrihydrite was primarily abiotic, being driven by biogenic sulfide. Sb and Fe K-edge X-ray absorption near edge structure (XANES) analysis showed reduction of Sb(V) to Sb(III) within 4 weeks, concurrent with DSR and the formation of FeS. Sb K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy analysis indicated that the reduced phase was a mixture of S- and O-coordinated Sb(III). Reduction of Sb(V) was not observed in the presence of magnetite, siderite, or green rust, and limited reduction occurred with vivianite. However, reduction of Sb(V) to amorphous Sb(III) sulfide occurred with mackinawite. These results are consistent with abiotic reduction of Sb(V) by biogenic sulfide and reveal a substantial influence of Fe oxides on the speciation of Sb(III), which illustrates the tight coupling of Sb speciation with the biogeochemical cycling of S and Fe. © 2021 Published by Elsevier Ltd.

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