Real-time speciation of uranium during active bioremediation and U(IV) reoxidation

John Komlos, Bhoopesh Mishra, Antonio Lanzirotti, Satish Chandra Babu Myneni, Peter R. Jaffe

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

The biological reduction of uranium from soluble U(VI) to insoluble U(IV) has shown potential to prevent uranium migration in groundwater. To gain insight into the extent of uranium reduction that can occur during biostimulation and to what degree U(IV) reoxidation will occur under field relevant conditions after biostimulation is terminated, X-ray absorption near edge structure (XANES) spectroscopy was used to monitor: (1) uranium speciation in situ in a flowing column while active reduction was occurring; and (2) in situ postbiostimulation uranium stability and speciation when exposed to incoming oxic water. Results show that after 70 days of bioreduction in a high (30 mM) bicarbonate solution, the majority (>90%) of the uranium in the column was immobilized as U(IV). After acetate addition was terminated and oxic water entered the column, in situ real-time XANES analysis showed that U(IV) reoxidation to U(VI) (and subsequent remobilization) occurred rapidly (on the order of minutes) within the reach of the oxygen front and the spatial and temporal XANES spectra captured during reoxidation allowed for real-time uranium reoxidation rates to be calculated.

Original languageEnglish (US)
Pages (from-to)78-86
Number of pages9
JournalJournal of Environmental Engineering
Volume134
Issue number2
DOIs
StatePublished - Jan 23 2008

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Civil and Structural Engineering
  • Environmental Chemistry
  • Environmental Science(all)

Keywords

  • Biodegradation
  • Iron
  • Oxidation
  • Rates
  • Uranium

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