Electrochemistry and Spectroscopy of UO2
 2+ in Addic AlCl3-EMIC

Anderson, Carolyn J.; Choppin, Gregory R.; Pruett, D.J.; Costa, David Antônio da; Smith, Wayne H.

doi:10.1524/ract.1999.84.1.31

Cited by 36 publications

(32 citation statements)

References 14 publications

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“…0.997 and 0.914 V. Formation of these waves is evidently due to the appearance of soluble uranium species participating in the electrochemical process. It is known [4,15] that uranium oxide species are converted into oxygen-free species upon introducing AlCl 3 into an RTIL. Probably, in our case oxygen-free uranium species were also present in solution.…”

Section: Resultsmentioning

confidence: 99%

Behavior of UO2 in a room-temperature ionic liquid in the presence of AlCl3

et al. 2004

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A study was made of interaction between AlCl 3 and room-temperature ionic liquid (RTIL) [C 8 H 15 N 2 ][N(SO 2 CF 3 ) 2 ], or BuEtIm!Tf 2 N, and of anodic dissolution in RTIL of UO 2 and of a simulated oxide fuel at 297!302 K, depending on the AlCl 3 concentration. It was shown that anodic dissolution of UO 2 pellets and a UO 2 !Al mixture in RTIL yields soluble uranium species. Potentiostatic electrolysis of the resulting solutions can yield uranium compounds at the cathode, though with low current efficiencies. The role of AlCl 3 in these processes was suggested. A heterophase reaction between UO 2 and AlCl 3 was studied, depending on the content of AlCl 3 in solution. It was found that the exchange reaction products, soluble uranium species, are accumulated in solution only at the molar ratio AlCl 3 /Tf 2 N > 1. Implementation of both pyrochemical and conventional aqueous methods of nuclear material processing involves certain problems. These include high operation costs, high corrosivity of structural materials, abundant waste, risk of accidents, etc.Low-temperature solvents such as room-temperature ionic liquids (RTILs) eliminate or, at least, significantly reduce some of the above-mentioned drawbacks. It is known [1!9] that RTILs are incombustible and virtually nonvolatile at process temperatures of up to 573 K; they exceed aqueous media in radiation resistance and exhibit a high selectivity with respect to the components being separated.It was of interest to study separation and purification of nuclear materials using such new process media as room-temperature ionic liquids, in particular, to study the possibility of utilization of uranium from the pressed mixture of 90 wt % Al with 10 wt % UO 2 , simulating the irradiated oxide fuel. To this end, we studied interaction of AlCl 3 and anodic dissolution of UO 2 and of the pressed Al!UO 2 mixture, as well as the exchange reaction between UO 2 and AlCl 3 in an RTIL of the composition [C 8 H 15 N 2 ][N(SO 2 CF 3 ) 2 ], or BuEtIm!Tf 2 N, at 297!302 K, depending on the AlCl 3 concentration. EXPERIMENTALWe studied the chemical and electrochemical behavior of UO 2 and Al!UO 2 mixture in BuEtIm!NTf 2 RTIL by linear and cyclic voltammetry and zerocurrent chronopotentiometry. Also, we carried out electrolysis of ionic liquids of different compositions, followed by the chemical and X-ray phase analyses of the solid and liquid phases.All manipulations, including assembling the electrochemical cells, were carried out in a dry glove box in an argon atmosphere. Argon was permanently freed from oxygen-containing impurities by forced circulation through a column packed with metallic Zr chips and heated to 1000 K. Argon circulation was effected by a membrane pump placed directly inside the glove box.As solvent we used RTIL of the composition BuEtIm!Tf 2 N, synthesized at the Los Alamos National Laboratory (the United States). Before use, the RTIL was additionally freed from oxygen-containing impurities by keeping at a residual pressure of 10 33 atm for 12 h.Electrochemical s...

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Section: Resultsmentioning

confidence: 99%

Behavior of UO2 in a room-temperature ionic liquid in the presence of AlCl3

et al. 2004

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“…Anderson and co-workers used spectroscopic methods to monitor the decomposition of UO 2 Cl 2 in an acidic AlCl 3 -[C 2 mim]Cl melt. 113 Also in studies on the mechanism of solvent extraction in ionic liquids, the absorption spectra of the uranyl ions were useful. 114 The intensities of the complex in ionic liquids were higher than those in acetonitrile, which was attributed to the stronger solvation in ionic liquids.…”

Section: Uraniummentioning

confidence: 99%

“…Surprisingly, UO 2 Cl 2 is not stable in an acidic chloroaluminate melt. 113 + become the dominant species. When the acidity of the melt is decreased further, UCl 4 will start to precipitate.…”

Section: Redox Behavior Of Uraniummentioning

confidence: 99%

“…In contrast to its behavior in acidic chloroaluminate ionic liquids, the uranyl ion is stable in basic ionic liquids. 113 The uranium(VI) ion can be reduced electrolytically to uranium-(IV) with the formation of the [ 114 The study shows that the uranium redox potential is sensitive to the cation of the ionic liquid. The highest sensitivity was found for the uranium(IV)/uranium-(III) redox couple.…”

Section: Redox Behavior Of Uraniummentioning

confidence: 99%

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Lanthanides and Actinides in Ionic Liquids

2007

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Koen Binnemans was born in Geel, Belgium, in 1970. He obtained his M. Sc. degree (1992) and Ph.D. degree (1996) in Chemistry at the Catholic University of Leuven, under the direction of Prof. C. Go ¨rller-Walrand. In the period 1999−2005, he was a postdoctoral fellow of the Fund for Scientific Research Flanders (Belgium). He did postdoctoral work with Prof. Jacques Lucas (Rennes, France) and Prof. Duncan W. Bruce (Exeter, U.K.). In 2000, he received the first ERES Junior Award (ERES, European Rare-Earth and Actinide Society). From 2002 until 2005, he was (parttime) associate professor. Presently, he is professor of chemistry at the Catholic University of Leuven. His current research interests are metalcontaining liquid crystals (metallomesogens), lanthanide-mediated organic reactions, lanthanide spectroscopy, supramolecular coordination chemistry, and ionic liquids.

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“…Choppin and coworkers [18] investigated the electrochemistry and spectroscopy of UO 2 2+ ions in acidic AlCl 3 -1-ethyl-3-methylimidazolium chloride ionic liquid and proposed the possible mechanisms for the conversion of U(VI) to U(III) using cyclic voltammetry. They also studied the redox behavior of U(IV) in basic melts [19].…”

Section: Introductionmentioning

confidence: 99%