Clays and Clay Minerals

, Volume 48, Issue 2, pp 266–271 | Cite as

Incorporation of Radioactive Contaminants into Pyroaurite-Like Phases by Electrochemical Synthesis

  • Y. RohEmail author
  • S. Y. Lee
  • M. P. Elless
  • J. E. Foss


During electrochemical remediation of radionuclide, 235U, 238U, and 99Tc-contaminated aqueous solutions, pyroaurite-like phases, ideally [M(II)M(III)(OH)16CO3·4H2O] where M = Fe, were synthesized following coprecipitation with iron from metal iron electrodes. The effect of radionuclides on the transformation of amorphous precipitates to crystalline pyroaurite-like phases was investigated using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray analysis, Fourier-transform infrared (FTIR) spectroscopy, and fluorescence spectroscopy. The synthetic iron carbonate hydroxide phases showed primary XRD peaks at 0.7 and 0.35 nm and FTIR spectra that indicated the presence of a brucite-like sheet structure with carbonate anions occupying the interlayer. Divalent and trivalent iron, eroded from the electrode, occupies the octahedral sites of the brucite-like sheets. The carbonate anions in the interlayer balance the excess positive charge from isomorphous substitution of the Fe2+ or Fe3+ by reduced uranium (U4+) and technetium (Tc4+). Because of the lower solubility associated with crystalline phases than amorphous phases, incorporation of radioactive contaminants into pyroaurite-like phases by electrochemical syntheses represents a more effective approach for removing U and Tc from contaminated aqueous solutions than traditional technologies.

Key Words

Coprecipitation Groundwater Remediation Pyroaurite Technetium Uranium Zero-Valent Iron 


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Copyright information

© The Clay Minerals Society 2000

Authors and Affiliations

  • Y. Roh
    • 1
    Email author
  • S. Y. Lee
    • 2
  • M. P. Elless
    • 3
  • J. E. Foss
    • 1
  1. 1.Department of Plant and Soil SciencesThe University of TennesseeKnoxvilleUSA
  2. 2.Environmental Sciences DivisionOak Ridge National LaboratoryOak RidgeUSA
  3. 3.Edenspace System CorporationRestonUSA

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