Time-Resolved Laser-Induced Fluorescence as a Unique Tool for Low-Level Uranium Speciation

Moulin, Christophe; Laszak, Ivan; Moulin, Valérie; Tondre, C.

doi:10.1366/0003702981944076

Cited by 139 publications

(133 citation statements)

References 26 publications

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“…The most striking discrepancies appear for the system U(VI)/H 2 O at various pH values, where, for the same species, lifetimes ranging from τ = (8.3 ± 0.3) µs 14 to τ = (80 ± 5) µs 12 have been reported, while differences in the position of the maximum of the emission peaks of more than 3 nm can be found in the literature. 12,15 Considering the great importance of U(VI) chemistry in relation to both its behaviour in natural systems and its relevance to studies by TRES, such discrepancies need to be elucidated in order to improve our understanding of the phenomena involved, and to obtain reliable values of both spectral maxima and lifetimes of the various species involved. To this end, the French Groupement de Recherches PRACTIS has sponsored the organization of a round-robin test aiming at defining the potential, together with the limitations, of TRES as a tool for the study of U(VI) behaviour in aqueous solution.…”

Section: Introductionmentioning

confidence: 91%

“…In the case where the log 10 K values would be assumed for the various equilibria, as is commonly done in the literature, 12,14,15,22,23,31,32 this would restrict the species attributions to those being present in the pH range for which the peaks are observed. In the case where the log 10 K values would be sought from the TRES measurements, as has been done for various systems, 8,14,33,36 this would set some limits to the equilibrium reaction constants involving these species.…”

Section: +mentioning

confidence: 99%

“…Chemical U(VI) studies with TRES include the determination of equilibrium and reaction rate constants [8][9][10] and analytical aspects such as the * corresponding author : isabelle.billard@ires.in2p3.fr detection of trace amounts of radioactive luminescent species. [11][12][13] From the above comments, it is clear that uranyl luminescence in solution is of interest to a large community of scientists for both fundamental and applied reasons.…”

Section: Introductionmentioning

confidence: 99%

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Aqueous Solutions of Uranium(VI) as Studied by Time-Resolved Emission Spectroscopy: A Round-Robin Test

et al. 2003

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Results are presented of an interlaboratory round-robin study of the application of timeResolved Emission Spectroscopy (TRES) to the speciation of uranium(VI) in aqueous media. This involved 13 independent laboratories, using various instrumental adevices and data 2 analysis methods. In some cases, experimental data from a laboratory were analysed using different softwares. Samples were prepared based on appropriate speciation diagrams and in general were found to be chemically stable for at least six months. Four different types of aqueous uranyl solutions were studied: (i) acidic medium where UO 2 2+ aq is the single emitting species, (ii) uranyl in the presence of fluoride ions, (iii) uranyl in the presence of sulfate ions, and (iv) uranyl in aqueous solutions under various pH conditions, promoting hydrolysed species. Results between the laboratories are compared in terms of number of decay components, luminescence lifetimes and spectral band positions. The potentials and limitations of TRES in uranyl analysis and speciation in aqueous solutions are discussed.

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Section: Introductionmentioning

confidence: 91%

Section: +mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Aqueous Solutions of Uranium(VI) as Studied by Time-Resolved Emission Spectroscopy: A Round-Robin Test

et al. 2003

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“…Time-resolved laser-induced fluorescence spectroscopy (TRLFS) is a unique, noninvasive, method (Table 1) for direct U speciation at concentrations typically measured in natural surface waters [34]. It has been used to identify and quantify UO 2 2+ and individual uranyl complexes with hydroxide, phosphate, sulfate, arsenate, and fulvate [34,35,36,37,38,39], based on calculated U speciation diagrams. While TRLFS is a promising technique for determining U speciation in natural waters, it is not suitable as a general method for all surface waters.…”

Section: Watermentioning

confidence: 99%

Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

Markich

2002

The Scientific World JOURNAL

201

142

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The speciation of uranium (U) in relation to its bioavailability is reviewed for surface waters (fresh-and seawater) and their sediments. A summary of available analytical and modeling techniques for determining U speciation is also presented. U(VI) is the major form of U in oxic surface waters, while U(IV) is the major form in anoxic waters. The bioavailability of U (i.e., its ability to bind to or traverse the cell surface of an organism) is dependent on its speciation, or physicochemical form. U occurs in surface waters in a variety of physicochemical forms, including the free metal ion (U 4+ or UO 2 2+ ) and complexes with inorganic ligands (e.g., uranyl carbonate or uranyl phosphate), and humic substances (HS) (e.g., uranyl fulvate) in dissolved, colloidal, and/or particulate forms. Although the relationship between U speciation and bioavailability is complex, there is reasonable evidence to indicate that UO 2 2+ and UO 2 OH + are the major forms of U(VI) available to organisms, rather than U in strong complexes (e.g., uranyl fulvate) or adsorbed to colloidal and/or particulate matter. U(VI) complexes with inorganic ligands (e.g., carbonate or phosphate) and HS apparently reduce the bioavailability of U by reducing the activity of UO 2 2+ and UO 2 OH + . The majority of studies have used the results from thermodynamic speciation modeling to support these conclusions. Time-resolved laser-induced fluorescence spectroscopy is the only analytical technique able to directly determine specific U species, but is limited in use to freshwaters of low pH and ionic strength. Nearly all of the available information relating the speciation of U to its bioavailability has been derived using simple, chemically defined experimental freshwaters, rather than natural waters. No data are available for estuarine or seawater. Furthermore, there are no available data on the relationship between U speciation and bioavailability in sediments. An understanding of this relationship has been hindered due to the lack of direct quantitative U speciation techniques for particulate phases. More robust analytical techniques for determining the speciation of U in natural surface waters are needed before the relationship between U speciation and bioavailability can be clarified.

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“…Since the 1940s, a number of studies on the complicated chemical reactions of U(VI) have been performed using various analytical methods such as spectrophotometry [2,3], ion exchange [4], colorimetry [5], potentiometry [6], and so on. However, there have been large discrepancies between literature data by some orders of magnitude due to the complexity and difficulty in making exact chemical speciation of U(VI).…”

Section: Introductionmentioning

confidence: 99%

Temperature-Dependent Hydrolysis Reactions of U(VI) Studied by TRLFS

Lee¹,

Yun²

2013

Journal of Nuclear Fuel Cycle and Waste Technology

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: Temperature-dependent hydrolysis behaviors of aqueous U(VI) species were investigated with time-resolved laserfluorescence spectroscopy (TRLFS) for (UO2)3(OH)7 -at 25°C and I = 0 M. The specific ion interaction theory (SIT) was applied for the extrapolation of the formation constants to infinitely diluted solution. The results of temperature-dependent hydrolysis behavior in terms of the U(VI) fluorescence were compared and validated with those obtained using computational methods (DQUANT and constant enthalpy equation). Both results matched well with each other. The reaction enthalpies and entropies that are vital for the computational methods were determined by a combination of the van't Hoff equation and the Gibbs free energy equation. The temperature-dependent hydrolysis reaction of the U(VI) species indicates the transition of a major U(VI)species by means of geothermal gradient and decay heat from the radioactive isotopes, representing the necessity of deeper consideration in the safety assessment of geologic repository.

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Time-Resolved Laser-Induced Fluorescence as a Unique Tool for Low-Level Uranium Speciation

Cited by 139 publications

References 26 publications

Aqueous Solutions of Uranium(VI) as Studied by Time-Resolved Emission Spectroscopy: A Round-Robin Test

Aqueous Solutions of Uranium(VI) as Studied by Time-Resolved Emission Spectroscopy: A Round-Robin Test

Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

Temperature-Dependent Hydrolysis Reactions of U(VI) Studied by TRLFS

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