State of uranyl phosphates and arsenates in aqueous solutions

Нипрук, О. В.; Черноруков, Н. Г.; Pykhova, Yu. P.; Godovanova, N. S.; Eremina, A. A.

doi:10.1134/s1066362211050067

Cited by 12 publications

(22 citation statements)

References 10 publications

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“…Despite a longer reaction time, Rui et al 26 observed only partial reduction of the hydrogen uranyl phosphate. With the presence of low solubility uranyl arsenate precipitates in our system (K sp of (UO 2 ) 3 (AsO 4 ) 2 ·12H 2 O is 4.07 × 10 −51 ), 13 we expect a decreased degree of U(VI) reduction where uranyl arsenate precipitates occur, which was confirmed in our system. There is also a possibility that the reduced U found in the precomb-U23000-As23000 sample resulted from reduction of U(VI) remaining in solution following uranyl arsenate precipitation rather than from the reduction of mineralized U(VI).…”

Section: Environmental Science and Technologysupporting

confidence: 78%

Simultaneous Reduction of Arsenic(V) and Uranium(VI) by Mackinawite: Role of Uranyl Arsenate Precipitate Formation

Troyer

Tang

Borch

2014

Environ. Sci. Technol.

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Uranium (U) and arsenic (As) often occur together naturally and, as a result, can be co-contaminants at sites of uranium mining and processing, yet few studies have examined the simultaneous redox dynamics of U and As. This study examines the influence of arsenate (As(V)) on the reduction of uranyl (U(VI)) by the redox-active mineral mackinawite (FeS). As(V) was added to systems containing 47 or 470 μM U(VI) at concentrations ranging from 0 to 640 μM. In the absence of As(V), U was completely removed from solution and fully reduced to nano-uraninite (nano-UO2). While the addition of As(V) did not reduce U uptake, at As(V) concentrations above 320 μM, the reduction of U(VI) was limited due to the formation of a trögerite-like uranyl arsenate precipitate. The presence of U also significantly inhibited As(V) reduction. While less U(VI) reduction to nano-UO2 may take place in systems with high As(V) concentrations, formation of trögerite-like mineral phases may be an acceptable reclamation end point due to their high stability under oxic conditions.

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Section: Environmental Science and Technologysupporting

confidence: 78%

Simultaneous Reduction of Arsenic(V) and Uranium(VI) by Mackinawite: Role of Uranyl Arsenate Precipitate Formation

Troyer

Tang

Borch

2014

Environ. Sci. Technol.

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“…For instance, uranyl phosphate complexes with a formula of (UO 2 ) 3 (PO 4 ) 2 ·4H 2 O form in solution with pH ranging from 1.5 to 9 [230]. These species remain stable at dilute concentrations because of their low solubility in water [179]. Experimentally, phosphate species can be investigated by detecting adsorbed species to SiO 2 crystals using ATR FT-IR spectroscopy [230].…”

Section: Surface Speciation Studied By Ir and Raman Spectroscopiesmentioning

confidence: 99%

“…The uranyl cation forms complexes with a wide range of oxyanions in aqueous solution, but only a handful of these have been systematically evaluated in solution. Some anions, particularly phosphate and vanadate, form solid compounds with low solubilities (10 −7 to 10 −9 M for uranyl phosphate and vanadates) [20,179,180]; thus, low concentrations in solution limit spectral characterization. Silicate forms a rather weak uranyl complex, and UO2(SiO(OH)3+ is the only major species observed between the narrow pH regime from 5 to 6.5.…”

Section: Chemical Identification and Dynamic Studies Of Soluble Uranymentioning

confidence: 99%

Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy

Haes

Forbes

2018

Coordination Chemistry Reviews

133

128

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The purpose of this review is to provide an overview of uranium speciation using vibrational spectroscopy methods including Raman and IR. Uranium is a naturally occurring, radioactive element that is utilized in the nuclear energy and national security sectors. Fundamental uranium chemistry is also an active area of investigation due to ongoing questions regarding the participation of 5f orbitals in bonding, variation in oxidation states and coordination environments, and unique chemical and physical properties. Importantly, uranium speciation affects fate and transportation in the environment, influences bioavailability and toxicity to human health, controls separation processes for nuclear waste, and impacts isotopic partitioning and geochronological dating. This review article provides a thorough discussion of the vibrational modes for U(IV), U(V), and U(VI) and applications of infrared absorption and Raman scattering spectroscopies in the identification and detection of both naturally occurring and synthetic uranium species in solid and solution states. The vibrational frequencies of the uranyl moiety, including both symmetric and asymmetric stretches are sensitive to the coordinating ligands and used to identify individual species in water, organic solvents, and ionic liquids or on the surface of materials. Additionally, vibrational spectroscopy allows for the in situ detection and real-time monitoring of chemical reactions involving uranium. Finally, techniques to enhance uranium species signals with vibrational modes are discussed to expand the application of vibrational spectroscopy to biological, environmental, inorganic, and materials scientists and engineers.

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“…The extended Debye-Hückel algorithm is used to compute activity coefficients. The PFLOTRAN thermodynamic database was expanded to include equilibrium constants for becquerelite and liebigite taken from Gorman-Lewis et al 31 and for troegerite from Nipruk et al, 32 and includes the most recent update to U complexes. 18,19,33 The geochemical system was described with eight primary species (UO 2 2+ , AsO 4 3− , Ca 2+ , Na + , H + , CO 3 2− , Cl − , and acetate − ).…”

Section: Speciation Calculationsmentioning

confidence: 99%

Effect of Bicarbonate, Calcium, and pH on the Reactivity of As(V) and U(VI) Mixtures

Gonzalez‐Estrella

Meza

Burns

et al. 2020

Environ. Sci. Technol.

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State of uranyl phosphates and arsenates in aqueous solutions

Cited by 12 publications

References 10 publications

Simultaneous Reduction of Arsenic(V) and Uranium(VI) by Mackinawite: Role of Uranyl Arsenate Precipitate Formation

Simultaneous Reduction of Arsenic(V) and Uranium(VI) by Mackinawite: Role of Uranyl Arsenate Precipitate Formation

Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy

Effect of Bicarbonate, Calcium, and pH on the Reactivity of As(V) and U(VI) Mixtures

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