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An improved thermodynamic model for the complexation of trivalent actinides and lanthanide with oxalic acid valid to high ionic strength.

Journal Article · · Chemical Geology
 [1];  [2];  [3]
  1. Sandia National Lab. (SNL-NM), Carlsbad, NM (United States)
  2. Florida State Univ., Tallahassee, FL (United States)
  3. Los Alamos National Lab. (LANL), Carlsbad, NM (United States)
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The dissociation constants of oxalic acid (Ox), and the stability constants of Am3+, Cm3+ and Eu3+ with Ox2– have been determined at 25 °C, over a range of concentration varying from 0.1 to 6.60 m NaClO4 using potentiometric titration and extraction techniques, respectively. The experimental data support the formation of complexes, M(Ox)n3 – 2n, where (M = Am3+, Cm3+ and Eu3+ and n = 1 and 2). The dissociation constant and the stability constant values measured as a function of NaClO4 concentration were used to estimate the Pitzer parameters for the respective interactions of Am3+, Cm3+ and Eu3+ with Ox. Furthermore, the stability constants data of Am3+ –Ox measured in NaClO4 and in NaCl solutions from the literature were simultaneously fitted in order to refine the existing actinide–oxalate complexation model that can be used universally in the safety assessment of radioactive waste disposal. The thermodynamic stability constant: log β0101 = 6.30 ± 0.06 and log β0102 = 10.84 ± 0.06 for Am3+ was obtained by simultaneously fitting data in NaCl and NaClO4 media. Additionally, log β0101 = 6.72 ± 0.08 and log β0102 = 11.05 ± 0.09 for the Cm3+ and log β0101 = 6.67 ± 0.08 and log β0102 = 11.15 ± 0.09 for the Eu3+ were calculated by extrapolation of data to zero ionic strength in NaClO4 medium only. For all stability constants, the Pitzer model gives an excellent representation of the data using interaction parameters β(0), β(1), and CΦ determined in this work. The thermodynamic model developed in this work will be useful in accurately modeling the potential solubility of trivalent actinides and early lanthanides to ionic strength of 6.60 m in low temperature environments in the presence of Ox. Furthermore, the work is also applicable to the accurate modeling transport of rare earth elements in various environments under the surface conditions.
Research Organization:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC04-94AL85000
OSTI ID:
1236228
Alternate ID(s):
OSTI ID: 1246575
Report Number(s):
SAND--2015-6902J; 599092
Journal Information:
Chemical Geology, Journal Name: Chemical Geology Journal Issue: C Vol. 413; ISSN 0009-2541
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (45)

Thermodynamic Properties of Brucite Determined by Solubility Studies and Their Significance to Nuclear Waste Isolation journal July 2008
Development of Accurate Chemical Equilibrium Models for Oxalate Species to High Ionic Strength in the System: Na—Ba—Ca—Mn—Sr—Cl—NO3—PO4—SO4—H2O at 25 °C journal December 2006
A Potentiometric, Spectrophotometric and Pitzer Ion-Interaction Study of Reaction Equilibria in the Aqueous H+-Al3+, H+-Oxalate and H+-Al3+-Oxalate Systems up to 5 mol⋅dm−3 NaCl journal October 2007
Re-evaluation of the First and Second Stoichiometric Dissociation Constants of Oxalic Acid at Temperatures from 0 to 60 °C in Aqueous Oxalate Buffer Solutions with or without Sodium or Potassium Chloride journal July 2009
The prediction of mineral solubilities in natural waters: the NaKMgCaClSO4H2O system from zero to high concentration at 25° C journal July 1980
The prediction of mineral solubilities in natural waters: The Na-K-Mg-Ca-H-Cl-SO4-OH-HCO3-CO3-CO2-H2O system to high ionic strengths at 25°C journal April 1984
The prediction of borate mineral equilibria in natural waters: Application to Searles Lake, California journal December 1986
Complex formation of La(III), Eu(III), Lu(III) and Am(III) with oxalate, sulphate, chloride and thiocyanate ions journal August 1964
Studies on EDTA complexes—VI mixed complexes of copper (II), nickel(II) and cobalt (II) versenates with pyridine, hydrazine, hydroxylamine, ethylenediamine and propylenediamine journal December 1965
Equilibrium studies of uranyl complexes—IV Reactions with carboxylic acids journal February 1967
Chemical equilibria in americium and curium sulphate and oxalate systems and an application of a liquid scintillation counting method journal May 1968
Mixed ligand chelates of copper(II) journal August 1969
Determination of the dissociation constants of oxalic acid and the ultraviolet spectra of the oxalate species in 3M perchlorate medium journal March 1983
Development of the FMT chemical transport simulator: Coupling aqueous density and mineral volume fraction to phase compositions journal February 1996
The aqueous geochemistry of REE. journal May 2000
Binary and ternary complexes of 1,3-phenylenediamine-N,N′-disuccinic acid with divalent cations journal January 1989
Inner versus outer sphere complexation of f-elements journal March 1997
Spectroscopic evaluation of thermodynamics of trivalent actinides in brines journal June 1998
Experimental investigations of the reaction path in the MgO–CO2–H2O system in solutions with various ionic strengths, and their applications to nuclear waste isolation journal June 2008
Experimental determination of solubilities of lead oxalate (PbC2O4(cr)) in a NaCl medium to high ionic strengths, and the importance of lead oxalate in low temperature environments journal March 2013
Experimental determination of the solubility constant for magnesium chloride hydroxide hydrate (Mg3Cl(OH)5·4H2O, phase 5) at room temperature, and its importance to nuclear waste isolation in geological repositories in salt formations journal August 2010
Improved thermodynamic model for interaction of EDTA with trivalent actinides and lanthanide to ionic strength of 6.60m journal May 2014
Ionic hydration and single ion activities in unassociated chlorides at high ionic strengths journal July 1970
Rate and Equilibrium Constants for the Formation of the Monooxalate Complex of Iron(III) journal November 1966
pH Standardization of 0.05 mol·kg -1 Tetraoxalate Buffer at Temperatures from (5 to 45) °C with Added KCl Molality up to 1.0 mol·kg -1 journal May 2007
Dissociation Constants of Oxalic Acid in Aqueous Sodium Chloride and Sodium Trifluoromethanesulfonate Media to 175 °C journal May 1998
Thermodynamic modeling of actinide complexation with oxalate at high ionic strength journal January 2001
Thermodynamics of Cm(III) in Concentrated Salt Solutions: Carbonate Complexation in NaCl Solution at 25°C journal April 1999
Thermodynamic Modeling of Actinide Complexation with Acetate and Lactate at High Ionic Strength journal January 1999
A potentiometric, spectrophotometric, and calorimetric investigation of molybdenum( VI )–oxalate complex formation journal January 1986
Complex formation in solutions of copper oxalate journal January 1960
Chélates du fer (III) avec des anions dicarboxylates journal April 1968
The Solubility of Am0HC03(c) and the Aqueous Thermodynamics of the System Na+-Am3+-HC03–-C032-0H--H20 journal January 1990
Variation of Stability Constants of Thorium and Uranium Oxalate Complexes with Ionic Strength journal January 1994
Thermodynamics of Neptunium(Y) in Concentrated Salt Solutions: Chloride Complexation and Ion Interaction (Pitzer) Parameters for the NpO+2 Ion journal January 1995
Thermodynamics of Neptunium(V) in Concentrated Salt Solutions: II. Ion Interaction (Pitzer) Parameters for Np(V) Hydrolysis Species and Carbonate Complexes journal January 1995
Complexation of Am(III) by Oxalate in NaClO4 Media journal January 1996
Thermodynamic Modeling of Neptunium(V)-Acetate Complexation in Concentrated NaCl Media journal January 1996
Variation of Stability Constants of Thorium Citrate Complexes with Ionic Strength journal January 1996
Neptunium(V) Complexation by Acetate, Oxalate and Citrate in NaClO4 Media at 25°C journal January 1997
Interaction of Neptunyl(V) and Uranyl(VI) with EDTA in NaCl Media: Experimental Study and Pitzer Modeling journal January 1998
Thermodynamic modeling of metal-ligand interactions in high ionic strength NaCl solutions: the Co2+-oxalate system journal January 2000
Thermodynamic modeling of metal–ligand interactions in high ionic strength NaCl solutions: the Ni2+-oxalate system journal January 2003
Modeling of Near Field Actinide Concentrations in Radioactive Waste Repositories in Salt Formations: Effect of Buffer Materials journal January 2000
Second dissociation constant of oxalic acid from 0 to 50 C, and the pH of certain oxalate buffer solutions journal May 1948

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Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
Am–Cm–Eu–oxalic acid complexation
Pitzer parameters
extraction
high ionic strength
oxalic acid dissociation constants