Direct determination of plutonium(V) and neptunium(V) complexation by carbonate ligand with CE‐ICP‐sector field MS

Topin, Sylvain; Aupiais, Jean; Moisy, Philippe

doi:10.1002/elps.200800656

Cited by 38 publications

(38 citation statements)

References 18 publications

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“…23 In the case of neptunium, there are not as many investigations as in the case of uranium, especially in seawater. 60 Again, these scattered data show the importance of using speciation methods to identify the uranium(VI)/neptunium(V) species present in seawater. 60 Again, these scattered data show the importance of using speciation methods to identify the uranium(VI)/neptunium(V) species present in seawater.…”

Section: Speciation Modelling In Seawatermentioning

confidence: 99%

XAS and TRLIF spectroscopy of uranium and neptunium in seawater

et al. 2015

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Seawater contains radionuclides at environmental levels; some are naturally present and others come from anthropogenic nuclear activity. In this report, the molecular speciation in seawater of uranium(VI) and neptunium(V) at a concentration of 5 × 10(-5) M has been investigated for the first time using a combination of two spectroscopic techniques: Time-resolved laser-induced fluorescence (TRLIF) for U and extended X-ray absorption fine structure (EXAFS) for U and Np at the LIII edge. In parallel, the theoretical speciation of uranium and neptunium in seawater at the same concentration is also discussed and compared to spectroscopic data. The uranium complex was identified as the neutral carbonato calcic complex UO2(CO3)3Ca2, which has been previously described in other natural systems. In the case of neptunium, the complex identified is mainly a carbonato complex whose exact stoichiometry is more difficult to assess. The knowledge of the actinide molecular speciation and reactivity in seawater is of fundamental interest in the particular case of uranium recovery and more generally regarding the actinide life cycle within the biosphere in the case of accidental release. This is the first report of actinide direct speciation in seawater medium that can complement inventory data.

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Section: Speciation Modelling In Seawatermentioning

confidence: 99%

XAS and TRLIF spectroscopy of uranium and neptunium in seawater

et al. 2015

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“…detection. The use of inductively coupled plasma mass spectrometers has also enabled low-level detection of lanthanides or actinides in studies aiming at determining their carbonate complexation constants [16,17]. With commercial CE instruments, it is now possible to perform measurements at a 5-601C temperature range enabling to determine thermodynamic parameters such as entropy and enthalpy of reactions, which have never yet been done with inorganic systems and require a precise control of the effective temperature inside the capillary.…”

Section: Introductionmentioning

confidence: 98%

Formation of CaSO₄(aq) and CaSeO₄(aq) studied as a function of ionic strength and temperature by CE

et al. 2009

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Ca(2+) complexation by both sulfate and selenate ligands was studied by CE. The species were observed to give a unique retention peak as a result of a fast equilibrium between the free ions and the complexes. The change in the corresponding retention time was interpreted with respect to the equilibrium constant of the complexation reaction. The results confirmed the formation of CaSO(4)(aq) and CaSeO(4)(aq) under our experimental conditions. The formation data were derived from the series of measurements carried out at about 15, 25, 35, 45 and 55 degrees C in 0.1 mol/L NaNO(3) ionic strength solutions, and in 0.5 and 1.0 mol/L NaNO(3) ionic strength solutions at 25 degrees C. Using a constant enthalpy of reaction enabled to fit all the experimental data in a 0.1 mol/L medium, leading to the thermodynamic parameters: Delta(r)G(0.1M)(25 degrees C)=-(7.59+/-0.23) kJ/mol, Delta(r)H(0.1 M)=5.57+/-0.80 kJ/mol, and Delta(r)S(0.1 M)(25 degrees C)=44.0+/-3.0 J mol(-1) K(-1) for CaSO(4)(aq) and Delta(r)G(0.1 M)(25 degrees C)=-(6.66+/-0.23) kJ/mol, Delta(r)H(0.1 M)=6.45+/-0.73 kJ/mol, and Delta(r)S(0.1 M)(25 degrees C)=44.0+/-3.0 J mol(-1) K(-1) for CaSeO(4)(aq). Both formation reactions were found to be endothermic and entropy driven. CaSO(4)(aq) appears to be more stable than CaSeO(4)(aq) by 0.93 kJ/mol under these experimental conditions, which correlates with the difference of acidity of the anions as expected for interactions between hard acids and hard bases according to the hard and soft acids and bases theory. The effect of the ionic medium on the formation constants was successfully treated using the Specific ion Interaction Theory, leading to significantly different binary coefficients epsilon(NA+,SO(2-)(4)) = -(0.15 +/- 0.06) mol/kg-1 and epsilon(NA+,SO(2-)(4)) = -(0.26 +/- 0.10) mol/kg-1.

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“…In the past few years, ACE has been widely used (i) to investigate chemical equilibria and measure stability constants of inorganic species and (ii) to determine the stable form of aqueous species [15,[17][18][19][20][21][22][23][24][25]. Models describing the formation of 1:1 complexes are often used [25][26][27] as well as models describing the formation of successive complexes using nonlinear regressions [15,17,19,21]. Moreover, commercial CE instruments perform measurements at a 5-60ЊC temperature range enabling to determine thermodynamic parameters such as entropy and enthalpy of reactions [25].…”

Section: Introductionmentioning

confidence: 99%

Formation of MSeO₄(aq) complexes (M²⁺ = Mg²⁺, Co²⁺, Ni²⁺, Cu²⁺, Cd²⁺) studied as a function of temperature by affinity capillary electrophoresis

2013

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Complexation of divalent cations (Mg(2+), Co(2+), Ni(2+), Cu(2+), Cd(2+)) by selenate ligand was studied by ACE (UV indirect detection) in 0.1 mol/L NaNO(3) ionic strength solutions at various temperatures (15, 25, 35, 45 and 55°C). For each solution, a unique peak was observed as a result of a fast equilibrium between the free ion and the complex (labile systems). The migration time corresponding to this peak changed as a function of the solution composition, namely the free and complexed metal concentrations, according to the complexation reactions. The results confirmed the formation of a unique 1:1 complex for each cation. The thermodynamic parameters were fitted to the experimental data at 0.1 mol/L ionic strength: (25°C) = -(6.5 ± 0.3), -(7.5 ± 0.3), -(7.7 ± 0.3), -(7.7 ± 0.3), and -(8.1 ± 0.3) kJ/mol and = 2.5 ± 0.2, 4.7 ± 0.4, 4.5 ± 0.6, 8.4 ± 1.1, and 7.2 ± 0.6 kJ/mol for M(2+) = Mg(2+), Co(2+), Ni(2+), Cu(2+), and Cd(2+), respectively. Complexes with alkaline earth and transition metal cations could be distinguished by their relative stabilities. The effect of the ionic medium was treated using the specific ion interaction theory and the thermodynamic parameters at infinite dilution were compared to previously published data on metal-selenate, metal-sulfate, and metal-chromate complexes.

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Direct determination of plutonium(V) and neptunium(V) complexation by carbonate ligand with CE‐ICP‐sector field MS

Cited by 38 publications

References 18 publications

XAS and TRLIF spectroscopy of uranium and neptunium in seawater

XAS and TRLIF spectroscopy of uranium and neptunium in seawater

Formation of CaSO₄(aq) and CaSeO₄(aq) studied as a function of ionic strength and temperature by CE

Formation of MSeO₄(aq) complexes (M²⁺ = Mg²⁺, Co²⁺, Ni²⁺, Cu²⁺, Cd²⁺) studied as a function of temperature by affinity capillary electrophoresis

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Direct determination of plutonium(V) and neptunium(V) complexation by carbonate ligand with CE‐ICP‐sector field MS

Cited by 38 publications

References 18 publications

XAS and TRLIF spectroscopy of uranium and neptunium in seawater

XAS and TRLIF spectroscopy of uranium and neptunium in seawater

Formation of CaSO4(aq) and CaSeO4(aq) studied as a function of ionic strength and temperature by CE

Formation of MSeO4(aq) complexes (M2+ = Mg2+, Co2+, Ni2+, Cu2+, Cd2+) studied as a function of temperature by affinity capillary electrophoresis

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Formation of CaSO₄(aq) and CaSeO₄(aq) studied as a function of ionic strength and temperature by CE

Formation of MSeO₄(aq) complexes (M²⁺ = Mg²⁺, Co²⁺, Ni²⁺, Cu²⁺, Cd²⁺) studied as a function of temperature by affinity capillary electrophoresis