Solvent extraction systems for mutual separation of Am(III) and Cm(III) from nitric acid solutions. A review of recent state-of-the-art

Matveev, Petr I.; Mohapatra, Prasanta K.; Kalmykov, Stepan N.; Петров, В. Г.

doi:10.1080/07366299.2020.1856998

Cited by 56 publications

(48 citation statements)

References 104 publications

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“…This approach has a great experience in technological applications, 6 including the concentration and separation of actinides. 7 One of the technological schemes for the reprocessing of the PUREX raffinate is the ExAm-process. 8,9 However, this complex system shows low separation factor for Am and light lanthanides and requires the use of additional separation stages.…”

Section: Introductionmentioning

confidence: 99%

Pyridine-di-phosphonates as chelators for trivalent f-elements: kinetics, thermodynamic and interfacial study of Am(iii)/Eu(iii) solvent extraction

et al. 2022

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Section: Introductionmentioning

confidence: 99%

Pyridine-di-phosphonates as chelators for trivalent f-elements: kinetics, thermodynamic and interfacial study of Am(iii)/Eu(iii) solvent extraction

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“…While the mechanism of proton release and metal binding in terms of MAL as well as the self-assembly of extractants into a stable aggregate is well-described, the acid and water molecules taken up into the solvent are often neglected . The theory showed that even though proton-exchange extractants do not readily extract acids from the aqueous phase, when in a concentrated system (in which most pilot and industrial processes are) the aggregation will be induced. The predicted speciation of the aggregates includes both acid and water molecules that are needed to stabilize the liquid polar core .…”

Section: Introductionmentioning

confidence: 99%

Molecular Forces in Liquid–Liquid Extraction

et al. 2021

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The phase transfer of ions is driven by gradients of chemical potentials rather than concentrations alone (i.e., by both the molecular forces and entropy). Extraction is a combination of high-energy interactions that correspond to short-range forces in the first solvation shell such as ion pairing or complexation forces, with supramolecular and nanoscale organization. While the latter are similar to the long-range solvent-averaged interactions in the colloidal world, in solvent extraction they are associated with lower characteristic lengths of the nanometric domain. Modeling of such complex systems is especially complicated because the two domains are coupled, whereas the resulting free energy of extraction is around k B T to guarantee the reversibility of the practical process. Nevertheless, quantification is possible by considering a partitioning of space among the polar cores, interfacial film, and solvent. The resulting free energy of transfer can be rationalized by utilizing a combination of terms which represent strong complexation energies, counterbalanced by various entropic effects and the confinement of polar solutes in nanodomains dispersed in the diluent, together with interfacial extractant terms. We describe here this ienaics approach in the context of solvent extraction systems; it can also be applied to further complex ionic systems, such as membranes and biological interfaces.

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“…The chemical isolation of trivalent minor actinide (An) elements from HLW is a complex task. HLW is a highly radioactive nitric acid solution (3–4 mol/L) that includes approximately half of the elements of the periodic table (As–Cm) . The most challenging chemical task is the separation of An(III)/Ln(III) because of their very similar chemical properties.…”

Section: Introductionmentioning

confidence: 99%

“…HLW is a highly radioactive nitric acid solution (3−4 mol/L) that includes approximately half of the elements of the periodic table (As− Cm). 5 The most challenging chemical task is the separation of An(III)/Ln(III) because of their very similar chemical properties. Lanthanide (Ln) elements must be separated because they are neutron poisons that will prevent the transmutation of Am.…”

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Way to Enforce Selectivity via Steric Hindrance: Improvement of Am(III)/Eu(III) Solvent Extraction by Loaded Diphosphonic Acid Esters

et al. 2021

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Hybrid donor extractants are a promising class of compounds for the separation of trivalent actinides and lanthanides. Here, we investigated a series of sterically loaded diphosphonate ligands based on bipyridine (BiPy-PO-iPr and BiPy-PO-cHex) and phenanthroline (Phen-PO-iPr and Phen-PO-cHex). We studied their complex formation with nitrates of trivalent f-elements in solvent extraction systems (Am and Eu) and homogeneous acetonitrile solutions (Nd, Eu, and Lu). Phenanthroline extractants demonstrated the highest efficiency and selectivity [SF(Am/Eu) up to 14] toward Am(III) extraction from nitric acid solutions among all of the studied diphosphonates of N-heterocycles. The binding constants established by UV–vis titration also indicated stronger binding of sterically impaired diphosphonates compared to the primary substituted diphosphonates. NMR titration and slope analysis during solvent extraction showed the formation of 2:1 complexes at high concentrations (>10–3 mol/L) for phenanthroline-based ligands. According to UV–vis titrations at low concentrations (10–5–10–6 mol/L), the phenanthroline-based ligands formed 1:1 complexes. Bipyridine-based ligands formed 1:1 complexes regardless of the ligand concentration. Luminescence titrations revealed that the quantum yields of the complexes with Eu(III) were 81 ± 8% (BiPy-PO-iPr) and 93 ± 9% (Phen-PO-iPr). Single crystals of the structures [Lu(μ2,κ4-(iPrO)2P(O)Phen(O)2(OiPr))(NO3)2]2 and Eu(Phen-PO-iPr)(NO3)3 were obtained by chemical synthesis with the Phen-PO-iPr ligand. X-ray diffraction studies revealed a closer contact of the f-element with the aromatic N atoms in the case of sterically loaded PO ligands compared with sterically deficient ligands. Density functional theory calculations allowed us to rationalize the observed selectivity trends in terms of the bond length, Mayer bond order, and preorganization energy.

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Solvent extraction systems for mutual separation of Am(III) and Cm(III) from nitric acid solutions. A review of recent state-of-the-art

Cited by 56 publications

References 104 publications

Pyridine-di-phosphonates as chelators for trivalent f-elements: kinetics, thermodynamic and interfacial study of Am(iii)/Eu(iii) solvent extraction

Pyridine-di-phosphonates as chelators for trivalent f-elements: kinetics, thermodynamic and interfacial study of Am(iii)/Eu(iii) solvent extraction

Molecular Forces in Liquid–Liquid Extraction

Way to Enforce Selectivity via Steric Hindrance: Improvement of Am(III)/Eu(III) Solvent Extraction by Loaded Diphosphonic Acid Esters

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