Fe(II) Induced Reduction of Incorporated U(VI) to U(V) in Goethite

Olwen Stagg, Katherine Morris, Andy Lam, Alexandra Navrotsky, Jesús M. Velázquez, Bianca Schacherl, Tonya Vitova, Jörg Rothe, Jurij Galanzew, Anke Neumann, Paul Lythgoe, Liam Abrahamsen-Mills, Samuel Shaw

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Over 60 years of nuclear activities have resulted in a global legacy of radioactive wastes, with uranium considered a key radionuclide in both disposal and contaminated land scenarios. With the understanding that U has been incorporated into a range of iron (oxyhydr)oxides, these minerals may be considered a secondary barrier to the migration of radionuclides in the environment. However, the long-term stability of U-incorporated iron (oxyhydr)oxides is largely unknown, with the end-fate of incorporated species potentially impacted by biogeochemical processes. In particular, studies show that significant electron transfer may occur between stable iron (oxyhydr)oxides such as goethite and adsorbed Fe(II). These interactions can also induce varying degrees of iron (oxyhydr)oxide recrystallization (<4% to >90%). Here, the fate of U(VI)-incorporated goethite during exposure to Fe(II) was investigated using geochemical analysis and X-ray absorption spectroscopy (XAS). Analysis of XAS spectra revealed that incorporated U(VI) was reduced to U(V) as the reaction with Fe(II) progressed, with minimal recrystallization (approximately 2%) of the goethite phase. These results therefore indicate that U may remain incorporated within goethite as U(V) even under iron-reducing conditions. This develops the concept of iron (oxyhydr)oxides acting as a secondary barrier to radionuclide migration in the environment.

Original languageEnglish (US)
Pages (from-to)16445-16454
Number of pages10
JournalEnvironmental Science and Technology
Volume55
Issue number24
DOIs
StatePublished - Dec 21 2021

Keywords

  • Fe(II)
  • HR-XANES
  • U(VI,V)
  • XAS
  • iron (oxyhydr)oxides

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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