The association of Europium(III) (Eu[III]) and Curium(III) (Cm[III]) with Chlorella vulgaris and with cellulose was studied by a batch method and time-resolved laser-induced fluorescence spectroscopy (TRLFS). The kinetics study performed by the batch method showed that maximum adsorption of Eu(III) and Cm(III) on C. vulgaris was attained within 3 min of contact; afterward, the percentage adsorption decreased with time due to chelation of the ions with exudates released from C. vulgaris with a strong affinity for Eu(III) and Cm(III). The TRLFS revealed that the short-term adsorption of Eu(III) on C. vulgaris was attributable to its coordination with cellulose on the algal cell wall. However, Eu(III) coordinated with the functional groups of cellulose very weakly despite the large distribution coefficients observed. These results indicate that the reactions, both at the cell's surfaces through adsorption and in solution phases through chelation with the exudates, are important in estimating the behavior of Eu(III) and Cm(III) in aqueous environments.
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http://dx.doi.org/10.1897/02-481 | DOI Listing |
ChemistryOpen
November 2024
Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, Tyne and Wear, NE1 8ST, UK.
Bis-1,2,4-triazine ligands are amongst the most promising soft N-donor ligands for the partitioning of trivalent actinides from trivalent lanthanides; a key separation proposed in the future reprocessing of spent nuclear fuels. In an effort to improve the extraction properties of these benchmark ligands, we propose herein a general ligand design approach that is inspired by the field of drug discovery, and we apply it to a new class of ligands in which the bidentate 3-(2-pyridyl)-1,2,4-triazine unit of the benchmark ligands is replaced by a bidentate 1,2,4-triazine-3-carboxamide unit. A series of nine novel ligands were synthesized by reactions of readily available ethyl 1,2,4-triazine-3-carboxylate building blocks with different polyamine cores and evaluated for their ability to extract and separate Am(III) and Cm(III) from Eu(III).
View Article and Find Full Text PDFRSC Adv
September 2024
Karlsruhe Institute of Technology (KIT), Institute for Nuclear Waste Disposal (INE) P.O. Box 3640 76021 Karlsruhe Germany
To improve the understanding of the extraction chemistry of An(iii) and Ln(iii) with N-donor ligands 2,6-bis(5-(-butyl)-1-pyrazol-3-yl)pyridine (C4-BPP) in the presence of 2-bromohexanoic acid was investigated. Extraction studies showed an excellent separation factor of SF ≈ 200 and SF ≈ 60 in comparison with the structurally similar ligand 2,6-bis(5-neopentyl-1-pyrazol-3-yl)pyridine C5-BPP (SF ≈ 100), even though C5-BPP showed significantly higher stability constants. Time-resolved laser fluorescence spectroscopy (TRLFS) studies revealed the formation of the ternary 1 : 1 and 1 : 2 complexes [Eu(C4-BPP) (2-bromohexanoate) ] ( = 1-2) ( and ).
View Article and Find Full Text PDFInorg Chem
July 2024
Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT), P.O. Box 3640, Karlsruhe 76021, Germany.
Dalton Trans
April 2024
Laboratory of Nuclear Energy Chemistry, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
Separation of lanthanide (Ln) and minor actinide (MA) elements and mutual separation between minor actinide elements ( Am(III) and Cm(III)) represent a crucial undertaking. However, separating these elements poses a significant challenge owing to their highly similar physicochemical properties. Asymmetric N-heterocyclic ligands such as -ethyl-6-(1-pyrazol-3-yl)--(-tolyl)picolinamide (Et--Tol-A-PzPy) and -ethyl--(-tolyl)-1,10-phenanthroline-2-carboxamide (ETPhenAm) have recently received considerable attention in the separation of MAs over Ln from acid solutions.
View Article and Find Full Text PDFEcotoxicol Environ Saf
October 2023
Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany. Electronic address:
Microorganisms show a high affinity for trivalent actinides and lanthanides, which play an important role in the safe disposal of high-level radioactive waste as well as in the mining of various rare earth elements. The interaction of the lanthanide Eu(III) with the sulfate-reducing microorganism Desulfosporosinus hippei DSM 8344, a representative of the genus Desulfosporosinus that naturally occurs in clay rock and bentonite, was investigated. Eu(III) is often used as a non-radioactive analogue for the trivalent actinides Pu(III), Am(III), and Cm(III), which contribute to a major part of the radiotoxicity of the nuclear waste.
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