A Study of U(VI) Hydrolysis and Carbonate Complexation by Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS)

Kato, Yoshiharu; Meinrath, G.; Kimura, Takaumi; Yoshida, Zenko

doi:10.1524/ract.1994.64.2.107

Cited by 96 publications

(105 citation statements)

References 16 publications

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“…In order to get information on the fluorescence intensity contribution of a species, an estimate of the absorption value of the species in a multicomponent mixture is required [20]: In principal, the fluorescence contributions of each species may be estimated from the lifetime curves, if the lifetimes of the species are sufficiently different and the lifetime of a species is larger than that of the electronically excited state. This behaviour has been observed previously [8,11] in solutions taken from U(VI) solid-aqueous phase equilibria.…”

Section: Resultssupporting

confidence: 85%

“…10 -3 M U(VI)) in perchlorate medium were studied by quantitative UV-Vis absorption spectroscopy and lifetime measurements. These data extend previous studies of U(VI) fluorescence at lower concentrations [8,11].…”

supporting

confidence: 90%

“…sulfuric and perchloric acid. The effect of perchloric acid, however, seems to be as pronounced as is the effect of sulfuric acid despite of the fact that perchloric acid certainly will not coordinate to U(VI) to an extent comparable to sulfuric acid [11,12].…”

Section: Introductionmentioning

confidence: 89%

“…Among those aspects, the fluorescence lifetime of U(VI) in aqueous solutions has to be mentioned. Fluorescence lifetimes depend on temperature [6], presence of quenchers [4,7], speciation [8][9][10] and ionic strength [11,12]. These dependencies, however, remain to be understood in detail [12].…”

Section: Introductionmentioning

confidence: 99%

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Lifetime and fluorescence quantum yield of uranium(VI) species in hydrolyzed solutions

Meinrath¹,

Lis²,

Stryla³

et al. 2000

Journal of Alloys and Compounds

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Section: Resultssupporting

confidence: 85%

supporting

confidence: 90%

Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Lifetime and fluorescence quantum yield of uranium(VI) species in hydrolyzed solutions

Meinrath¹,

Lis²,

Stryla³

et al. 2000

Journal of Alloys and Compounds

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“…7). At pH 4.5, various hydrolysis products of uranyl [UO 2 OH ϩ , (UO 2 ) 2 (OH) 2 2ϩ , and (UO 2 ) 3 (OH) 5 ϩ ] are dominant (19,21,39), having been formed by complexation with hydroxyl anions. Samples from polyphosphate-packed cells shortly after uranyl challenge and polyphosphate-lacking cells challenged with uranyl showed similar spectra.…”

Section: Resultsmentioning

confidence: 99%

Uranyl Precipitation byPseudomonas aeruginosavia Controlled Polyphosphate Metabolism

Renninger¹,

Knopp²,

Nitsche

et al. 2004

Appl Environ Microbiol

108

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The polyphosphate kinase gene from Pseudomonas aeruginosa was overexpressed in its native host, resulting in the accumulation of 100 times the polyphosphate seen with control strains. Degradation of this polyphosphate was induced by carbon starvation conditions, resulting in phosphate release into the medium. The mechanism of polyphosphate degradation is not clearly understood, but it appears to be associated with glycogen degradation. Upon suspension of the cells in 1 mM uranyl nitrate, nearly all polyphosphate that had accumulated was degraded within 48 h, resulting in the removal of nearly 80% of the uranyl ion and >95% of lesser-concentrated solutions. Electron microscopy, energy-dispersive X-ray spectroscopy, and time-resolved laser-induced fluorescence spectroscopy (TRLFS) suggest that this removal was due to the precipitation of uranyl phosphate at the cell membrane. TRLFS also indicated that uranyl was initially sorbed to the cell as uranyl hydroxide and was then precipitated as uranyl phosphate as phosphate was released from the cell. Lethal doses of radiation did not halt phosphate secretion from polyphosphate-filled cells under carbon starvation conditions.Biological methods for the removal of heavy metals and actinides have recently been investigated due to their cost effectiveness at moderate metal concentrations. Many strains have been isolated that sorb (14,23,51,59,61), reduce (10, 18, 52, 56), and precipitate (4, 33, 41, 44, 45) metals, usually on the outer membrane of the cell. Sorption is generally achieved in a reversible process and is dependent on the composition of the water being treated, as other chelating agents compete with the complexing moieties on the cell. Thus, the applicability of this method in more complex waste streams or environments may be somewhat suspect due to the relatively low binding affinities of cellular components for metals compared to chelators, such as humic or organic acids. Reduction is generally limited to anaerobic processes and is ineffective against single-oxidationstate metals. Precipitation has the advantage of producing chemically stable forms of metal, and its use is not limited to reducible metals.With respect to the biological precipitation of metals, both metal sulfides (12,57,58,60) and metal phosphates (4, 33, 45) have been investigated due to their low solubilities. While some work has been done to produce sulfide aerobically (57), its production is generally an anaerobic process, limiting its applicability. The release of phosphate via the hydrolysis of an organic phosphate has been shown to be an effective method for the precipitation of metals on cell membranes. Macaskie and Dean (30) isolated a cadmium-resistant strain of Citrobacter that precipitated numerous metals, such as uranyl ion, as metal phosphates through the use of a membranebound acid phosphatase (26,31,32). Using glycerol-2-phosphate as a phosphate source, the organism cleaved phosphate from the source in the periplasmic space, leaving it to bind with metals that had been complexe...

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Uranium and Uranium Compounds

Clark¹,

Keogh²,

Neu³

et al. 2000

Kirk-Othmer Encyclopedia of Chemical Technology

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An overview of uranium and uranium compounds with an emphasis on their relevance to chemical technology is provided. Uranium and its compounds have many uses both potential and applied, examples include nuclear fuel, radiation shielding, and kinetic energy penetrators. These uses have a substantial economic impact, the aspects of which are provided. Sections are provided which illustrate the occurrence, recovery, and radiochemistry of uranium as well as the properties and preparation of uranium metal. A broad overview of uranium coordination and organometallic compounds is also provided. Drawbacks to the application of uranium and uranium compounds in many processes include the chemical reactivity of the metal and the inherent radioactivity of uranium isotopes. As such, health and safety factors which must be taken into account while working with uranium are discussed.

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A Study of U(VI) Hydrolysis and Carbonate Complexation by Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS)

Cited by 96 publications

References 16 publications

Lifetime and fluorescence quantum yield of uranium(VI) species in hydrolyzed solutions

Lifetime and fluorescence quantum yield of uranium(VI) species in hydrolyzed solutions

Uranyl Precipitation byPseudomonas aeruginosavia Controlled Polyphosphate Metabolism

Uranium and Uranium Compounds

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