Sequestration of trivalent americium and lanthanide nitrates with bis-lactam-1,10-phenanthroline ligand in a hydrocarbon solvent

Karslyan, Yana; Sloop, Frederick V.; Delmau, Lætitia H.; Moyer, Bruce A.; Popovs, Ilja; Paulenová, Alena; Jansone‐Popova, Santa

doi:10.1039/c9ra06115k

Cited by 20 publications

(6 citation statements)

References 24 publications

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“…Besides the above ligands, 1,10-phenanthroline-derived ligands with hard–soft donors combined in the same molecule also show the potential to separate Ans(III) from Lns(III), which have attracted extensive attention recently. − For example, a novel tetradentate ligand, N , N′ -diethyl- N , N′ -ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen) (Figure ), can selectively extract Am(III) ( D Am = 6, SF Am/Eu = 67) from excess Eu(III) at 1 M HNO 3 . Meanwhile, the ligand also has a strong affinity for actinides with higher valence states, such as Th(IV), U(VI), and Pu(IV), so it is expected to be a candidate ligand for group separation of actinides .…”

Section: Introductionmentioning

confidence: 99%

Selective Separation of Am(III)/Eu(III) by the QL-DAPhen Ligand under High Acidity: Extraction, Spectroscopy, and Theoretical Calculations

Wang

Yang

et al. 2021

Inorg. Chem.

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Although 1,10-phenanthroline-based ligands have recently shown vast opportunities for the separation of trivalent actinides (Ans(III)) from lanthanides (Lns(III)), the optimization and design of the extractant structure based on the phenanthroline framework remain hotspots for further improving the separation. Following the strategy of hard and soft donor atom combination, for the first time, the quinoline group was attached to the 1,10-phenanthroline skeleton, giving a lipophilic ligand, 2,9-diacyl-bis((3,4-dihydroquinoline-1((2H)-yl)-1),10-phenanthroline (QL-DAPhen)), for Am(III)/Eu(III) separation. In the presence of sodium nitrate, the ligand can effectively extract Am(III) over Eu(III) in HNO 3 solution, with the separation factor (SF Am/Eu ) ranging from 29 to 44. The coordination chemistry of Eu(III) with QL-DAPhen was investigated by slope analysis, NMR titration, UV−vis titration, Fourier transform infrared spectroscopy, electrospray ionization-mass spectrometry, and theoretical calculations. The experimental results unanimously confirm that the ligand forms both 1:1 and 1:2 complexes with Eu(III), and the stability constants (log β) of each of the two complexes were obtained. Density functional theory calculations show that the Am−N bonds have more covalent characteristics than the Eu−N bonds in the complexes, which reveals the reason why the ligand preferentially bonds with Am(III). Meanwhile, the thermodynamic analysis reveals that the 1:1 complex is more thermodynamically stable than the 1:2 complex. The findings of this work have laid a solid theoretical foundation for the application of phenanthrolinebased ligands in the separation of An(III) from practical systems.

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Section: Introductionmentioning

confidence: 99%

Selective Separation of Am(III)/Eu(III) by the QL-DAPhen Ligand under High Acidity: Extraction, Spectroscopy, and Theoretical Calculations

Wang

Yang

et al. 2021

Inorg. Chem.

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“…High D values indicate better extraction efficiency and imply the formation of stable Ln(III) complexes in the organic phase. Ligands that show great promise in REE separations include diglycolamides (DGA), − alkylated bis-triazinyl pyridines (BTP), and 2,9-bis-lactam-1,10-phenanthroline (BLPhen), , among others. − Extraction performance is also impacted by experimental conditions, including solvent, temperature, and volume of each phase. Organic solvents such as toluene, n-dodecane, 1-octanol, and dichloroethane are commonly used to carry out the liquid–liquid separations.…”

Section: Introductionmentioning

confidence: 99%

Advancing Rare-Earth Separation by Machine Learning

Liu

Johnson

Jansone‐Popova

et al. 2022

JACS Au

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Constituting the bulk of rare-earth elements, lanthanides need to be separated to fully realize their potential as critical materials in many important technologies. The discovery of new ligands for improving rare-earth separations by solvent extraction, the most practical rare-earth separation process, is still largely based on trial and error, a low-throughput and inefficient approach. A predictive model that allows high-throughput screening of ligands is needed to identify suitable ligands to achieve enhanced separation performance. Here, we show that deep neural networks, trained on the available experimental data, can be used to predict accurate distribution coefficients for solvent extraction of lanthanide ions, thereby opening the door to high-throughput screening of ligands for rare-earth separations. One innovative approach that we employed is a combined representation of ligands with both molecular physicochemical descriptors and atomic extended-connectivity fingerprints, which greatly boosts the accuracy of the trained model. More importantly, we synthesized four new ligands and found that the predicted distribution coefficients from our trained machine-learning model match well with the measured values. Therefore, our machine-learning approach paves the way for accelerating the discovery of new ligands for rare-earth separations.

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“…Among the organic ligands, mixed N- and O-donor (N,O-hybrid) ligands have been actively studied in recent years due to their great potential in separating actinides from the lanthanides. − The separation is based on the concept that the relatively softer N donor atoms contribute to the ligand’s discriminating ability between actinides and lanthanides by forming stronger bonds of more covalency with actinides, while the hard O donor atoms enhance the overall complexation strength to ensure appreciable extraction or masking of Actinides. For example, the hydrophilic diethylenetriaminepentaacetic acid has long been used as a selective masking agent in the TALSPEAK process for trivalent actinide/lanthanide separation .…”

Section: Introductionmentioning

confidence: 99%

Probing the Difference in the Complexation of Trivalent Actinides and Lanthanides with a Tridentate N,O-Hybrid Ligand: Spectroscopy, Thermodynamics, and Coordination Modes

Cao

Wei

et al. 2022

Inorg. Chem.

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Comparatively revealing the complexation behavior of trivalent actinides and lanthanides with functional ligands in aqueous solution is of great importance to enrich our knowledge on the fundamental coordination chemistry of trivalent f-block elements and to control the fate of minor actinides in nuclear fuel cycles. In this work, the complexation of Am(III) and Nd(III), representatives for trivalent actinides and lanthanides, respectively, with a N,O-hybrid ligand 6-(dimethylcarbamoyl)picolinic acid (DMAPA, denoted as HL) was investigated by absorption spectroscopy, calorimetry, X-ray crystallography, and density functional theory (DFT) calculations. Successive formation of 1:1, 1:2, and 1:3 (metal/ligand) complexes of Am(III) and Nd(III) with DMAPA was identified, and the corresponding thermodynamic parameters were determined. The binding strength of Am(III) with DMAPA is slightly stronger than that of Nd(III), and the complexation of Nd(III) with DMAPA is mainly entropy-driven. The crystal structure of the 1:2 Nd(III)/DMAPA complex and the DFT calculation shed additional light on the coordination and structural characteristics of the complexes. In contrast to the Nd−N bond in the Nd(III)/DMAPA complex, the Am−N bond in the Am(III)/DMAPA complex exhibits more covalency, which contributes to the slightly stronger complexation of Am(III) with DMAPA.

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Sequestration of trivalent americium and lanthanide nitrates with bis-lactam-1,10-phenanthroline ligand in a hydrocarbon solvent

Abstract: Efficient separation of trivalent americium and light lanthanides from aqueous acidic medium into hydrocarbon solvent using BLPhen extractant.

Cited by 20 publications

References 24 publications

Selective Separation of Am(III)/Eu(III) by the QL-DAPhen Ligand under High Acidity: Extraction, Spectroscopy, and Theoretical Calculations

Selective Separation of Am(III)/Eu(III) by the QL-DAPhen Ligand under High Acidity: Extraction, Spectroscopy, and Theoretical Calculations

Advancing Rare-Earth Separation by Machine Learning

Probing the Difference in the Complexation of Trivalent Actinides and Lanthanides with a Tridentate N,O-Hybrid Ligand: Spectroscopy, Thermodynamics, and Coordination Modes

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