Synergic Extraction of Uranium(VI) from Different Aqueous Media Using HTTA and Neutral Donors

On-Line Speciation of Uranyl Chelates in Supercritical CO2 by Time-Resolved Laser-Induced Fluorescence Spectroscopy

“…The chelates UO 2 TTA 2 ·TBP and UO 2 (NO 3 ) 2 ·2TBP were selected for speciation studies because they are the principal complexes being considered for an industrial uranium SFE, and the process may result in an extraction of a mixture of these complexes . When used together, TTA and TBP have been reported to have a synergistic effect upon metal extraction efficiency. ,− The TTA and TBP ligands also allow for selective uranium complexation, and both of the resulting complexes have high ScF solubilities. − ,,,,,

3 Normalized emission, integrated over the wavelength range 450−650 nm, as a function of time for UO 2 (NO 3 ) 2 ·2TBP (τ = 2200 ns) and UO 2 TTA 2 ·TBP (τ = 42 ns) in ScF CO 2 (50 °C, 200 atm, 1.0 mL/min). The primary coordinating ligand clearly has a significant effect upon the emission decay time.

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“…Multiligand Extraction. Recent studies have shown that uranium can be efficiently extracted from nitric acid solutions with TBP-modified ScF CO 2 . ,, β-diketones have been widely employed, and the combination of TTA and TBP has been shown to have a synergistic effect for both conventional and ScF extractions of uranium. ,− Figure shows normalized spectra from on-line TRLIF monitoring of a mixed-ligand extraction of 7.0 mL of 0.01 M UO 2 2+ in 1 N nitric acid with ScF CO 2 , at 150 atm and 50 °C, modified with 0.15 M TBP and 0.05 M TTA. Detector gate parameters clearly allow the spectra from the complexes UO 2 TTA 2 ·TBP (0−250 ns) and UO 2 (NO 3 ) 2 ·2TBP (0.25−10 μs) to be resolved on-line.…”