Redox interactions of Tc(VII), U(VI), and Np(V) with microbially reduced biotite and chlorite

Diana R. Brookshaw, Richard A.D. Pattrick, Pieter Bots, Gareth T. W. Law, Jonathan R. Lloyd, J. Fredrick W. Mosselmans, David J. Vaughan, Kathy Dardenne, Katherine Morris

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Abstract

Technetium, uranium, and neptunium are contaminants that cause concern at nuclear facilities due to their long half-life, environmental mobility, and radiotoxicity. Here we investigate the impact of microbial reduction of Fe(III) in biotite and chlorite and the role that this has in enhancing mineral reactivity toward soluble TcO4 -, UO2 2+, and NpO2 +. When reacted with unaltered biotite and chlorite, significant sorption of U(VI) occurred in low carbonate (0.2 mM) buffer, while U(VI), Tc(VII), and Np(V) showed low reactivity in high carbonate (30 mM) buffer. On reaction with the microbially reduced minerals, all radionuclides were removed from solution with U(VI) reactivity influenced by carbonate. Analysis by X-ray absorption spectroscopy (XAS) confirmed reductive precipitation to poorly soluble U(IV) in low carbonate conditions and both Tc(VII) and Np(V) in high carbonate buffer were also fully reduced to poorly soluble Tc(IV) and Np(IV) phases. U(VI) reduction was inhibited under high carbonate conditions. Furthermore, EXAFS analysis suggested that in the reaction products, Tc(IV) was associated with Fe, Np(IV) formed nanoparticulate NpO2, and U(IV) formed nanoparticulate UO2 in chlorite and was associated with silica in biotite. Overall, microbial reduction of the Fe(III) associated with biotite and chlorite primed the minerals for reductive scavenging of radionuclides: this has clear implications for the fate of radionuclides in the environment.
Original languageEnglish
Pages (from-to)13139-13148
Number of pages10
JournalEnvironmental Science and Technology
Volume49
Issue number22
Early online date21 Oct 2015
DOIs
Publication statusPublished - 17 Nov 2015

Fingerprint

Carbonates
chlorite
biotite
carbonate
Radioisotopes
Minerals
radionuclide
Buffers
Neptunium
mineral
neptunium
technetium
X ray absorption spectroscopy
Uranium
Technetium
Scavenging
atomic absorption spectroscopy
Reaction products
Silicon Dioxide
half life

Keywords

  • nuclear facilities
  • radiotoxicity
  • microbial reduction
  • carbonation
  • nanoparticulate
  • biotite
  • chlorite
  • minerals
  • X-ray absorption spectroscopy

Cite this

Brookshaw, D. R., Pattrick, R. A. D., Bots, P., Law, G. T. W., Lloyd, J. R., Mosselmans, J. F. W., ... Morris, K. (2015). Redox interactions of Tc(VII), U(VI), and Np(V) with microbially reduced biotite and chlorite. Environmental Science and Technology , 49(22), 13139-13148. https://doi.org/10.1021/acs.est.5b03463
Brookshaw, Diana R. ; Pattrick, Richard A.D. ; Bots, Pieter ; Law, Gareth T. W. ; Lloyd, Jonathan R. ; Mosselmans, J. Fredrick W. ; Vaughan, David J. ; Dardenne, Kathy ; Morris, Katherine. / Redox interactions of Tc(VII), U(VI), and Np(V) with microbially reduced biotite and chlorite. In: Environmental Science and Technology . 2015 ; Vol. 49, No. 22. pp. 13139-13148.
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abstract = "Technetium, uranium, and neptunium are contaminants that cause concern at nuclear facilities due to their long half-life, environmental mobility, and radiotoxicity. Here we investigate the impact of microbial reduction of Fe(III) in biotite and chlorite and the role that this has in enhancing mineral reactivity toward soluble TcO4 -, UO2 2+, and NpO2 +. When reacted with unaltered biotite and chlorite, significant sorption of U(VI) occurred in low carbonate (0.2 mM) buffer, while U(VI), Tc(VII), and Np(V) showed low reactivity in high carbonate (30 mM) buffer. On reaction with the microbially reduced minerals, all radionuclides were removed from solution with U(VI) reactivity influenced by carbonate. Analysis by X-ray absorption spectroscopy (XAS) confirmed reductive precipitation to poorly soluble U(IV) in low carbonate conditions and both Tc(VII) and Np(V) in high carbonate buffer were also fully reduced to poorly soluble Tc(IV) and Np(IV) phases. U(VI) reduction was inhibited under high carbonate conditions. Furthermore, EXAFS analysis suggested that in the reaction products, Tc(IV) was associated with Fe, Np(IV) formed nanoparticulate NpO2, and U(IV) formed nanoparticulate UO2 in chlorite and was associated with silica in biotite. Overall, microbial reduction of the Fe(III) associated with biotite and chlorite primed the minerals for reductive scavenging of radionuclides: this has clear implications for the fate of radionuclides in the environment.",
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Brookshaw, DR, Pattrick, RAD, Bots, P, Law, GTW, Lloyd, JR, Mosselmans, JFW, Vaughan, DJ, Dardenne, K & Morris, K 2015, 'Redox interactions of Tc(VII), U(VI), and Np(V) with microbially reduced biotite and chlorite', Environmental Science and Technology , vol. 49, no. 22, pp. 13139-13148. https://doi.org/10.1021/acs.est.5b03463

Redox interactions of Tc(VII), U(VI), and Np(V) with microbially reduced biotite and chlorite. / Brookshaw, Diana R.; Pattrick, Richard A.D.; Bots, Pieter; Law, Gareth T. W.; Lloyd, Jonathan R.; Mosselmans, J. Fredrick W.; Vaughan, David J.; Dardenne, Kathy; Morris, Katherine.

In: Environmental Science and Technology , Vol. 49, No. 22, 17.11.2015, p. 13139-13148.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Redox interactions of Tc(VII), U(VI), and Np(V) with microbially reduced biotite and chlorite

AU - Brookshaw, Diana R.

AU - Pattrick, Richard A.D.

AU - Bots, Pieter

AU - Law, Gareth T. W.

AU - Lloyd, Jonathan R.

AU - Mosselmans, J. Fredrick W.

AU - Vaughan, David J.

AU - Dardenne, Kathy

AU - Morris, Katherine

PY - 2015/11/17

Y1 - 2015/11/17

N2 - Technetium, uranium, and neptunium are contaminants that cause concern at nuclear facilities due to their long half-life, environmental mobility, and radiotoxicity. Here we investigate the impact of microbial reduction of Fe(III) in biotite and chlorite and the role that this has in enhancing mineral reactivity toward soluble TcO4 -, UO2 2+, and NpO2 +. When reacted with unaltered biotite and chlorite, significant sorption of U(VI) occurred in low carbonate (0.2 mM) buffer, while U(VI), Tc(VII), and Np(V) showed low reactivity in high carbonate (30 mM) buffer. On reaction with the microbially reduced minerals, all radionuclides were removed from solution with U(VI) reactivity influenced by carbonate. Analysis by X-ray absorption spectroscopy (XAS) confirmed reductive precipitation to poorly soluble U(IV) in low carbonate conditions and both Tc(VII) and Np(V) in high carbonate buffer were also fully reduced to poorly soluble Tc(IV) and Np(IV) phases. U(VI) reduction was inhibited under high carbonate conditions. Furthermore, EXAFS analysis suggested that in the reaction products, Tc(IV) was associated with Fe, Np(IV) formed nanoparticulate NpO2, and U(IV) formed nanoparticulate UO2 in chlorite and was associated with silica in biotite. Overall, microbial reduction of the Fe(III) associated with biotite and chlorite primed the minerals for reductive scavenging of radionuclides: this has clear implications for the fate of radionuclides in the environment.

AB - Technetium, uranium, and neptunium are contaminants that cause concern at nuclear facilities due to their long half-life, environmental mobility, and radiotoxicity. Here we investigate the impact of microbial reduction of Fe(III) in biotite and chlorite and the role that this has in enhancing mineral reactivity toward soluble TcO4 -, UO2 2+, and NpO2 +. When reacted with unaltered biotite and chlorite, significant sorption of U(VI) occurred in low carbonate (0.2 mM) buffer, while U(VI), Tc(VII), and Np(V) showed low reactivity in high carbonate (30 mM) buffer. On reaction with the microbially reduced minerals, all radionuclides were removed from solution with U(VI) reactivity influenced by carbonate. Analysis by X-ray absorption spectroscopy (XAS) confirmed reductive precipitation to poorly soluble U(IV) in low carbonate conditions and both Tc(VII) and Np(V) in high carbonate buffer were also fully reduced to poorly soluble Tc(IV) and Np(IV) phases. U(VI) reduction was inhibited under high carbonate conditions. Furthermore, EXAFS analysis suggested that in the reaction products, Tc(IV) was associated with Fe, Np(IV) formed nanoparticulate NpO2, and U(IV) formed nanoparticulate UO2 in chlorite and was associated with silica in biotite. Overall, microbial reduction of the Fe(III) associated with biotite and chlorite primed the minerals for reductive scavenging of radionuclides: this has clear implications for the fate of radionuclides in the environment.

KW - nuclear facilities

KW - radiotoxicity

KW - microbial reduction

KW - carbonation

KW - nanoparticulate

KW - biotite

KW - chlorite

KW - minerals

KW - X-ray absorption spectroscopy

U2 - 10.1021/acs.est.5b03463

DO - 10.1021/acs.est.5b03463

M3 - Article

VL - 49

SP - 13139

EP - 13148

JO - Environmental Science and Technology

JF - Environmental Science and Technology

SN - 0013-936X

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