Extraction and thermodynamic behavior of U(VI) and Th(IV) from nitric acid solution with tri-isoamyl phosphate

Kong, Fanzuo; Liao, Jiali; Ding, Songdong; Yang, Yuanyou; Huang, Huang; Yang, Jijun; Tang, Jun; Liu, Ning

doi:10.1007/s10967-013-2482-2

Cited by 13 publications

(3 citation statements)

References 24 publications

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“…Organic extractants have been playing an important role in separating uranium from thorium for a long time due to their chelating properties. Phosphates/phosphonates for U(VI)/Th(IV) purification are especially widely utilized in the extraction and recovery of hexavalent uranyl (UO 2 2+ ) and tetravalent thorium from effluents of nuclear power plants. − However, a solution of phosphates/phosphonates (like tri- n -butyl phosphate, TBP) in dodecane or other inert aliphatics is often used in practice, as pure TBP alone is too viscous to operate with . This may lead to a massive volume of organic wastes and introduce additional issue to deal with.…”

Section: Introductionmentioning

confidence: 99%

Polypropylene Modified with Amidoxime/Carboxyl Groups in Separating Uranium(VI) from Thorium(IV) in Aqueous Solutions

Xiong

Liu

et al. 2017

ACS Sustainable Chem. Eng.

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A majority of U/Th reprocessing studies are hampered in the production of large amounts of radioactive waste during extraction with organic complexes from highly acidic solutions. Polypropylene grafted with amidoxime/ carboxyl groups (PPAC), which exhibits selective binding toward U(VI), can help reduce organic waste. Batch studies on PPAC separating U(VI) from U(VI)/Th(IV) mixture in acidic to weak alkaline solution with complexing agent EDTA were carried out. The result suggested a much better affinity of PPAC to U(VI) over Th(IV). The pH effect study suggested the largest U/Th mass ratio at pH ∼8. FTIR spectra at different pHs indicated most of the carboxyl and amidoxime functional groups were protonated at lower pH, while with increasing pH, the deprotonating degree increased correspondingly. X-ray diffraction analysis showed U(VI) and Th(IV) could both enter the crystal lattice, resulting in smaller diffraction angle which was associated with U(VI) and Th(IV) adsorption capacity. This work revealed polymer or other material with amidoxime/carboxyl groups is a promising candidate for deployment as a uranium adsorbent in U/Th reprocessing.

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Section: Introductionmentioning

confidence: 99%

Polypropylene Modified with Amidoxime/Carboxyl Groups in Separating Uranium(VI) from Thorium(IV) in Aqueous Solutions

Xiong

Liu

et al. 2017

ACS Sustainable Chem. Eng.

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“…These degraded products not only reduce the fission product decontamination efficiency by forming a complex between fission products and degraded products but also prevent the complete stripping of uranium and plutonium which is lost in the raffinate (solvent wash waste). In addition to the formation of low soluble metal (like Th, Zr, Pu) complexes of HDBP and H 2 MBP, sometimes these complexes are precipitated and create obstacles in the operation. − …”

Section: Introductionmentioning

confidence: 99%

“…It has already been reported that TiAP, a homologous of TBP, is a potential ligand in many aspects, such as: TiAP has less of a tendency toward third phase formation for the extraction of tetravalent actinides, lower aqueous solubility (0.019 kg/m 3 ) compared to TBP (0.40 kg/m 3 ), high extraction ability, and better resistance to degradation . In literature, also, it has been mentioned that TiAP might be a replacement of TBP and is being used for thermal reactor fuel reprocessing as well as fast reactor fuel reprocessing. − Further, though triethylphosphate (TEP) has not been reported in the literature for its use as a metal ion extractant, few experimental thermophysical data are available for it which are useful to calibrate the atomistic force field. Therefore, a detailed investigation on the structural and thermophysical properties of these ligands and the related dynamical properties for the metal extraction is of utmost necessary for which molecular level studies are essential to predict structural and thermophysical properties with an aim to have a better understanding of the extraction process. − …”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation for the Calibration of the OPLS Force Field Using DFT Derived Partial Charges for the Screening of Alkyl Phosphate Ligands by Studying Structure, Dynamics, and Thermodynamics

2017

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Molecular dynamics (MD) simulations were performed to calibrate the all-atom optimized potential for liquid simulations (OPLS-AA) force field using partial quantum charges calculated from four different population analysis methods: Mulliken, Löwdin, NPA, and ChelpG for predicting the thermophysical properties of pure liquids like tri-n-butylphosphate (TBP), tri-isoamylphosphate (TiAP), triethylphosphate (TEP), and dodecane to determine a potential solvent for the nuclear fuel cycle. The structural, dynamic, and thermodynamic properties were calculated in NVT ensembles by introducing the partial charges on each atom calculated from density functional theory (DFT). The calculated structural and dynamic properties were affected by the different partial charges on TBP, TiAP, and TEP. The estimated liquid density employing partial charges obtained from Mulliken population analysis with OPLS force field leads to an excellent agreement with the experimental data (within 0.36–1.41%). The diffusivity and the pair correlation function (PCF) for all of the ligands have been calculated and validated wherever literature data is available. The free energies of hydration and solvation for all of the ligands were evaluated using thermodynamic integration technique and the hydration free energy for TEP is within 8.3% of the experimental value, and for other properties they are not available in the literature for comparison. Furthermore, the partition coefficient of the ligands calculated using MD derived free energy difference between the water–dodecane system resembles the trend predicted by DFT/COSMO-RS calculations which is in qualitative agreement with the experimental results. Among the four-charge model, the computed dipole moment of TBP and TEP using the Mulliken charge is found to be in good agreement with the experimental results. Finally, the superiority of TiAP over TBP as an extracting agent for the UO2 2+ ion has been demonstrated by a higher calculated free energy of extraction, ΔG ext, over TBP using DFT. Overall the Mulliken charge embedded calibrated OPLS-AA force field is perhaps the most reliable one as it does not incorporate any arbitrary scaling in the force field or Lennard–Jones parameters and thus can be used indubitably to evaluate the liquid state properties of alkyl phosphates and n-alkanes which eventually assist in the invent of future generation extractants.

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Extraction kinetics of Uranium(VI) and Thorium(IV) with Tri-iso-amyl phosphate from nitric acid using a Lewis Cell

Liu

Kong

Liao

et al. 2014

J Radioanal Nucl Chem

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Extraction and thermodynamic behavior of U(VI) and Th(IV) from nitric acid solution with tri-isoamyl phosphate

Cited by 13 publications

References 24 publications

Polypropylene Modified with Amidoxime/Carboxyl Groups in Separating Uranium(VI) from Thorium(IV) in Aqueous Solutions

Polypropylene Modified with Amidoxime/Carboxyl Groups in Separating Uranium(VI) from Thorium(IV) in Aqueous Solutions

Molecular Dynamics Simulation for the Calibration of the OPLS Force Field Using DFT Derived Partial Charges for the Screening of Alkyl Phosphate Ligands by Studying Structure, Dynamics, and Thermodynamics

Extraction kinetics of Uranium(VI) and Thorium(IV) with Tri-iso-amyl phosphate from nitric acid using a Lewis Cell

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