Selenium Speciation Assessed by X-Ray Absorption Spectroscopy of Sequentially Extracted Anaerobic Biofilms

M. Lenz, E.D. van Hullebusch, F. Farges, S. Nikitenko, C.N. Borca, D. Grolimund, P.N.L. Lens

Research output: Contribution to journalArticleAcademicpeer-review

28 Citations (Scopus)

Abstract

Wet chemical methods such as sequential extraction procedures are commonly used to assess selenium fractionation in anoxic environments, allowing an estimation of the mobility and bioavailability of selenium. However, the interpretation can be biased by unselective extraction of targeted species and artifacts introduced during the extraction. Here,the selectivity of the single extraction steps to gain reliable selenium speciation information are scrutinized for the first time by direct nondestructive X-ray absorption near edge structure (XANES) spectroscopy at the selenium K-edge. The sequential extraction procedures seriously overestimated the elemental selenium fraction, as major parts (58%) of the total selenium were present as metal selenides and organic selenium compounds, although extracted in the elemental fraction. Spectral fitting of the XANES spectra by the least-squares linear combinations utilizing a large set of model compounds, including previously neglected Se(-I) selenides, showed a novel degree of complexity in the speciation of selenium treating anaerobic biofilms, with up to 4 modeled selenium species contributing to the speciation, i.e., different elemental, organic, and metal-bound selenium species. Furthermore, a short exposure (10 min) to ambient air during the sequential extraction procedure induced the oxidation of organic selenium compounds, revealing the fragility of selenium speciation in anaerobic biofilms.
Original languageEnglish
Pages (from-to)7587-7593
JournalEnvironmental Science and Technology
Volume42
Issue number20
DOIs
Publication statusPublished - 2008

Fingerprint

X ray absorption spectroscopy
Biofilms
atomic absorption spectroscopy
Selenium
selenium
X-ray spectroscopy
biofilm
Selenium Compounds
Metals
X ray absorption near edge structure spectroscopy
XANES spectroscopy
X ray absorption
Fractionation
metal
chemical method
ambient air
bioavailability
artifact
fractionation
Oxidation

Keywords

  • granular sludge
  • elemental selenium
  • anoxic sediments
  • selenate
  • reduction
  • sulfate
  • fractionation
  • bacteria
  • soils
  • forms

Cite this

Lenz, M., van Hullebusch, E. D., Farges, F., Nikitenko, S., Borca, C. N., Grolimund, D., & Lens, P. N. L. (2008). Selenium Speciation Assessed by X-Ray Absorption Spectroscopy of Sequentially Extracted Anaerobic Biofilms. Environmental Science and Technology, 42(20), 7587-7593. https://doi.org/10.1021/es800811q
Lenz, M. ; van Hullebusch, E.D. ; Farges, F. ; Nikitenko, S. ; Borca, C.N. ; Grolimund, D. ; Lens, P.N.L. / Selenium Speciation Assessed by X-Ray Absorption Spectroscopy of Sequentially Extracted Anaerobic Biofilms. In: Environmental Science and Technology. 2008 ; Vol. 42, No. 20. pp. 7587-7593.
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abstract = "Wet chemical methods such as sequential extraction procedures are commonly used to assess selenium fractionation in anoxic environments, allowing an estimation of the mobility and bioavailability of selenium. However, the interpretation can be biased by unselective extraction of targeted species and artifacts introduced during the extraction. Here,the selectivity of the single extraction steps to gain reliable selenium speciation information are scrutinized for the first time by direct nondestructive X-ray absorption near edge structure (XANES) spectroscopy at the selenium K-edge. The sequential extraction procedures seriously overestimated the elemental selenium fraction, as major parts (58{\%}) of the total selenium were present as metal selenides and organic selenium compounds, although extracted in the elemental fraction. Spectral fitting of the XANES spectra by the least-squares linear combinations utilizing a large set of model compounds, including previously neglected Se(-I) selenides, showed a novel degree of complexity in the speciation of selenium treating anaerobic biofilms, with up to 4 modeled selenium species contributing to the speciation, i.e., different elemental, organic, and metal-bound selenium species. Furthermore, a short exposure (10 min) to ambient air during the sequential extraction procedure induced the oxidation of organic selenium compounds, revealing the fragility of selenium speciation in anaerobic biofilms.",
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Lenz, M, van Hullebusch, ED, Farges, F, Nikitenko, S, Borca, CN, Grolimund, D & Lens, PNL 2008, 'Selenium Speciation Assessed by X-Ray Absorption Spectroscopy of Sequentially Extracted Anaerobic Biofilms', Environmental Science and Technology, vol. 42, no. 20, pp. 7587-7593. https://doi.org/10.1021/es800811q

Selenium Speciation Assessed by X-Ray Absorption Spectroscopy of Sequentially Extracted Anaerobic Biofilms. / Lenz, M.; van Hullebusch, E.D.; Farges, F.; Nikitenko, S.; Borca, C.N.; Grolimund, D.; Lens, P.N.L.

In: Environmental Science and Technology, Vol. 42, No. 20, 2008, p. 7587-7593.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Selenium Speciation Assessed by X-Ray Absorption Spectroscopy of Sequentially Extracted Anaerobic Biofilms

AU - Lenz, M.

AU - van Hullebusch, E.D.

AU - Farges, F.

AU - Nikitenko, S.

AU - Borca, C.N.

AU - Grolimund, D.

AU - Lens, P.N.L.

N1 - ISI:000259988400010

PY - 2008

Y1 - 2008

N2 - Wet chemical methods such as sequential extraction procedures are commonly used to assess selenium fractionation in anoxic environments, allowing an estimation of the mobility and bioavailability of selenium. However, the interpretation can be biased by unselective extraction of targeted species and artifacts introduced during the extraction. Here,the selectivity of the single extraction steps to gain reliable selenium speciation information are scrutinized for the first time by direct nondestructive X-ray absorption near edge structure (XANES) spectroscopy at the selenium K-edge. The sequential extraction procedures seriously overestimated the elemental selenium fraction, as major parts (58%) of the total selenium were present as metal selenides and organic selenium compounds, although extracted in the elemental fraction. Spectral fitting of the XANES spectra by the least-squares linear combinations utilizing a large set of model compounds, including previously neglected Se(-I) selenides, showed a novel degree of complexity in the speciation of selenium treating anaerobic biofilms, with up to 4 modeled selenium species contributing to the speciation, i.e., different elemental, organic, and metal-bound selenium species. Furthermore, a short exposure (10 min) to ambient air during the sequential extraction procedure induced the oxidation of organic selenium compounds, revealing the fragility of selenium speciation in anaerobic biofilms.

AB - Wet chemical methods such as sequential extraction procedures are commonly used to assess selenium fractionation in anoxic environments, allowing an estimation of the mobility and bioavailability of selenium. However, the interpretation can be biased by unselective extraction of targeted species and artifacts introduced during the extraction. Here,the selectivity of the single extraction steps to gain reliable selenium speciation information are scrutinized for the first time by direct nondestructive X-ray absorption near edge structure (XANES) spectroscopy at the selenium K-edge. The sequential extraction procedures seriously overestimated the elemental selenium fraction, as major parts (58%) of the total selenium were present as metal selenides and organic selenium compounds, although extracted in the elemental fraction. Spectral fitting of the XANES spectra by the least-squares linear combinations utilizing a large set of model compounds, including previously neglected Se(-I) selenides, showed a novel degree of complexity in the speciation of selenium treating anaerobic biofilms, with up to 4 modeled selenium species contributing to the speciation, i.e., different elemental, organic, and metal-bound selenium species. Furthermore, a short exposure (10 min) to ambient air during the sequential extraction procedure induced the oxidation of organic selenium compounds, revealing the fragility of selenium speciation in anaerobic biofilms.

KW - granular sludge

KW - elemental selenium

KW - anoxic sediments

KW - selenate

KW - reduction

KW - sulfate

KW - fractionation

KW - bacteria

KW - soils

KW - forms

U2 - 10.1021/es800811q

DO - 10.1021/es800811q

M3 - Article

VL - 42

SP - 7587

EP - 7593

JO - Environmental Science and Technology

JF - Environmental Science and Technology

SN - 0013-936X

IS - 20

ER -