A study on the extraction of actinides with a novel carboxylic acid extractant

Xu, Chao; Zhu, Liyang; Liu, Qian; Yang, Suliang; Xue, Yun; Tian, Guoxin

doi:10.1007/s10967-022-08706-2

Cited by 4 publications

(7 citation statements)

References 23 publications

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“…The ligand 6carboxylic di(2-ethylhexyl)amide pyridine (DEHAPA) (Figure 1b) contains a pyridine skeleton and other two functional groups, carboxylic acid and amide. 28,29 DEHAPA has good solubility in nonpolar diluents, such as kerosene and toluene. Unfortunately, no extraction of trivalent actinides Am(III) and Cm(III) is observed when the pH value is less than 1.6.…”

Section: ■ Introductionmentioning

confidence: 99%

Enhancing the Selectivity of Trivalent Actinide over Lanthanide Using Asymmetrical Phenanthroline Diamide Ligands

Wang,

Yang,

Liu

et al. 2024

Inorg. Chem.

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Phenanthroline diamide ligands have been widely used in the separation of trivalent actinides and lanthanides, but little research has focused on extractants with asymmetrical substitutes. Two novel asymmetrical phenanthroline-based ligands N 2,N 2,N 9-triethyl-N 9-tolyl-1,10-phenanthroline-2,9-dicarboxamide (DE-ET-DAPhen) and N 2-ethyl-N 9,N 9-dioctyl-N 2-tolyl-1,10-phenanthroline-2,9-dicarboxamide (DO-ET-DAPhen) were first synthesized in this work, whose extraction ability and complexation mechanism to trivalent actinides [An(III)] and lanthanides [Ln(III)] were systematically investigated. The ligands dissolved in n-octanol exhibit good extraction ability and high selectivity toward Am(III) in acidic solutions. The complexation mechanism of the ligands with Ln(III) in solution and solid state was analyzed using slope analysis, 1H NMR spectrometric titration, ESI-MS, and calorimetric titration. It is revealed that the ligands complex with Am(III)/Eu(III) with 1:1 stoichiometry. The stability constant (log β) of the complexation reaction of Eu(III) with DE-ET-DAPhen determined by UV–vis spectrophotometric and calorimetric titration is higher than that of DO-ET-DAPhen, indicating the stronger complexation ability of DE-ET-DAPhen. Meanwhile, the calorimetric titration results show that the complexation process is exothermic with a decreased entropy. The structures of 1:1 complexes of Eu(III) and Nd(III) with DE-ET-DAPhen were analyzed through single-crystal X-ray diffraction. This work proves that ligands containing asymmetrical functional groups are promising for An(III)/Ln(III) separation, which shows great significance in efficient extractants designed for the spent nuclear fuel reprocessing process.

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Section: ■ Introductionmentioning

confidence: 99%

Enhancing the Selectivity of Trivalent Actinide over Lanthanide Using Asymmetrical Phenanthroline Diamide Ligands

Wang,

Yang,

Liu

et al. 2024

Inorg. Chem.

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“…The decreasing stability constants in the order of U(VI) > Np(VI) > Pu(VI) suggested the stronger affinity of DMAPA to U(VI). Xu et al then replaced the methyl group of DMAPA with the 2-diethylhexyl group to obtain a novel ligand 6-carboxylic di(2-ethylhexyl) amide pyridine (DEHAPA), which was proven to have a certain ability to separate U(VI) and Th(IV). However, the distributions of U(VI) and Th(IV) by DEHAPA were only 0.9 and 0.15 at 1 M HNO 3 , respectively, which was significantly lower than that of DAPhen.…”

Section: Introductionmentioning

confidence: 99%

Selective Extraction of Uranium(VI) from Thorium(IV) Using New Unsymmetrical Acidic Phenanthroline Carboxamide Ligands

Wang,

Yang,

et al. 2023

Ind. Eng. Chem. Res.

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In the thorium−uranium fuel cycle, 232 Th will produce fissional 233 U and radioactive 232 U simultaneously after irradiation. The selective separation of uranium from thorium-based spent fuel can enhance the utilization efficiency of nuclear fuel and promote the safety of nuclear energy utilization. In this work, a new type of unsymmetrical acidic phenanthroline carboxamide ligand represented as 9-(N,N-dialkylcarbamoyl)-1,10-phenanthroline-2-carboxylic acid (DEAPA and DOAPA) was synthesized for selective separation of U(VI) over Th(IV). The separation of small amounts of U(VI) from large amounts of Th(IV) could be achieved by using DOAPA to extract at high acidity (4 M HNO 3 ) and then using 1 M HNO 3 as the stripping agent. The complexation mechanism of these two ligands with U(VI) and Th(IV) was investigated through slope analysis, NMR spectrometric titration, UV−vis spectrophotometric titration, and single-crystal Xray diffraction methods. Results from slope analysis and NMR spectrometric titration showed that DOAPA formed a 1:1 complex with U(VI) and formed 1:1 and 1:2 complexes with Th(IV). The larger stability constants (log β) of 1:1 complexes of DEAPA/DOAPA with U(VI) than those with Th(IV) implied the stronger affinity of the ligands with U(VI), which was in good coincidence with the solvent extraction results. The crystal structures of the 1:1 complex of U(VI) and the two species of 1:1 and 1:2 complexes of Th(IV) with DEAPA were successfully analyzed by X-ray diffraction. This work provided a new type of unsymmetrical acidic phenanthroline carboxamide extractant for the efficient separation of U(VI) from Th(IV). The systematic study of the extraction and complexation behavior would be helpful to explore the effect of functional groups as well as design extractants with excellent performance.

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“…Some commonly used extractants are phosphorus-containing extractants, 20−22 chelating extractants, 23 amine extractants, 24,25 and carboxylic acid extractants. 26,27 2.2. Synthesis of the Extractant DMDDOPDA.…”

Section: Introductionmentioning

confidence: 99%

“…Some commonly used extractants are phosphorus-containing extractants, 20−22 chelating extractants, 23 amine extractants, 24,25 and carboxylic acid extractants. 26,27 chloromethane, toluene, and a mixture of n-dodecane and isooctanol (1:1, v/v)] are clarified. 2.2.…”

Section: Introductionmentioning

confidence: 99%

“…In general, the purity of REEs, especially that of Dy and Nd, produced by solvent extraction is higher than that produced by conventional precipitation , because solvent extraction shows better selectivity for the target metals. Some commonly used extractants are phosphorus-containing extractants, − chelating extractants, amine extractants, , and carboxylic acid extractants. , However, they have certain drawbacks such as low extraction efficiency, difficulty in back-extraction, small separation coefficient, and high price as well as a tendency to form a third phase. In addition, the extraction of Dy(III) and Nd(III) is still challenging because of issues such as low extraction rate, ineffective stripping, and poor separation …”

Section: Introductionmentioning

confidence: 99%

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Solvent Extraction of Dy(III) and Nd(III) with an Unsymmetrical Pentanediamide Extractant

Xiong,

Huang,

et al. 2023

Ind. Eng. Chem. Res.

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Recovery of rare-earth elements (REEs), especially those of Dy and Nd, from Nd−Fe−B permanent magnets is crucial for sustainable development. Herein, an unsymmetrical pentanediamide extractant, N,N′-dimethyl-N,N′-didecyl-3-oxapentanediamide (DMDDOPDA), was synthesized and characterized for the effective extraction of Dy(III) and Nd(III). DMDDOPDA can form coordination bonds with metal ions because of the strong electron-donating abilities of the N and O atoms. The coordination sites might be inclined toward one side during the extraction. DMDDOPDA exhibited superior extraction performance in the HNO 3 system than it did in the HCl system. The highest extraction efficiencies of Dy(III) and Nd(III) under optimal conditions were 99.9% and 99.5%, respectively, while their optimum stripping efficiencies were 100% and 85.3%, respectively. DMDDOPDA extraction of Dy(III) and Nd(III) in the four investigated diluents involved the formation of a neutral coordination complex. This study provides new insights into REE extraction using pentanediamide extractants.

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A study on the extraction of actinides with a novel carboxylic acid extractant

Cited by 4 publications

References 23 publications

Enhancing the Selectivity of Trivalent Actinide over Lanthanide Using Asymmetrical Phenanthroline Diamide Ligands

Enhancing the Selectivity of Trivalent Actinide over Lanthanide Using Asymmetrical Phenanthroline Diamide Ligands

Selective Extraction of Uranium(VI) from Thorium(IV) Using New Unsymmetrical Acidic Phenanthroline Carboxamide Ligands

Solvent Extraction of Dy(III) and Nd(III) with an Unsymmetrical Pentanediamide Extractant

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