Supercritical Fluid Extraction of Plutonium and Americium from Soil using Thenoyltrifluoroacetone and Tributylphosphate Complexation
Samples of clean soil from the source used to backfill pits at the Idaho National Engineering and Environmental Laboratory's Radioactive Waste Management Complex were spiked with Pu-239 and Am-241 to evaluate ligand-assistedsupercritical fluid extraction as a decontamination method. The actual soil in the pits has been subject to approximately three decades of weatheringsince it was originally contaminated. No surrogate soil can perfectly simulate the real event, but actual contaminated soil was not available for research purposes. However, fractionation of Am and Pu in the surrogate soil was found to be similar to that previously measured in the real soil using asequential aqueous extraction procedure. This suggests that Pu and Am behavior are similar in the two soils. The surrogate was subjected to supercritical carbon dioxide extraction, in the presence of the fluorinated beta diketone thenoyltrifluoroacetone (TTA), and tributylphosphate (TBP). As much as 69% of the Pu and 88% of the Am were removed from the soil using 3.2mol% TTA and 2.7 mol % TBP, in a single 45 minute extraction. Extraction conditions employing a 5 mol % ethanol modifier with 0.33 mol % TTA and 0.27 mol %TBP resulted in 66% Pu and 68% Am extracted. To our knowledge, this is thefirst report of the use of supercritical fluid extraction (SFE) for the removal of actinides from soil.
- Research Organization:
- Idaho National Laboratory (INL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC07-99ID13727
- OSTI ID:
- 912117
- Report Number(s):
- INEEL/JOU-00-00904
- Journal Information:
- Radiochimica Acta, Journal Name: Radiochimica Acta Journal Issue: 10 Vol. 89
- Country of Publication:
- United States
- Language:
- English
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