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Cm(III) speciation in the presence of citrate from neutral to hyperalkaline conditions and the effect of calcium.
Comins, Matthew B; Shang, Chengming; Polly, Robert; Skerencak-Frech, Andrej; Altmaier, Marcus; Hixon, Amy E; Gaona, Xavier.
Afiliación
  • Comins MB; Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, 301 Stinson-Remick, Notre Dame, IN, 46556, USA. Electronic address: mbcomins@gmail.com.
  • Shang C; Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, Karlsruhe, 76021, Germany. Electronic address: colombe.chengming.shang@gmail.com.
  • Polly R; Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, Karlsruhe, 76021, Germany. Electronic address: polly@kit.edu.
  • Skerencak-Frech A; Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, Karlsruhe, 76021, Germany. Electronic address: andrej.skerencak@kit.edu.
  • Altmaier M; Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, Karlsruhe, 76021, Germany. Electronic address: marcus.altmaier@kit.edu.
  • Hixon AE; Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, 301 Stinson-Remick, Notre Dame, IN, 46556, USA. Electronic address: ahixon@nd.edu.
  • Gaona X; Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, Karlsruhe, 76021, Germany. Electronic address: xavier.gaona@kit.edu.
Chemosphere ; 364: 143233, 2024 Aug 31.
Article en En | MEDLINE | ID: mdl-39222691
ABSTRACT
We investigated the binary Cm-citrate system using time-resolved laser fluorescence spectroscopy (TRLFS), parallel factor analysis (PARAFAC), and quantum chemical calculations. Evidence collectively suggests the stepwise coordination and deprotonation of citrate alcohol groups in Cm-cit complexes with two bound citrate moieties upon increasing pH, which is supported by a bathochromic shift in emission spectra, an observed increase in lifetime measurements, and lower energy minima for citrate alcohol involvement versus hydrolysis of the Cm-citrate species. Our PARAFAC results agree with a 3-component model for the Cm-citrate system and offer pure component decompositions, yielding fraction species across the studied pH range that have a correlated slope = 1 as a function of pH. For the first time, evidence of ternary Ca-Cm-citrate complexes was revealed by TRLFS with increasing calcium concentration at fixed pHm. The formation of these ternary complexes was substantiated with density functional theory (DFT) calculations on simple model systems of the complexes. Shared citrate carboxylate groups between calcium and curium were proposed for all three ternary Ca-Cm-cit complexes based on DFT-determined Ca-O and Cm-O distances. Moreover, we found that the ternary complex with both alcohol groups deprotonated is most stable when it shares both two carboxylate and two alcohol groups between Ca and Cm. The presence of shared functional groups highlights the enhanced stability of these ternary complexes. Additional work is warranted to further constrain the stoichiometry, stability constants and dependence on ionic strength of these complexes for purposes of thermodynamic modeling of repository settings.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: Chemosphere Año: 2024 Tipo del documento: Article Pais de publicación: Reino Unido
Texto completo
Añadir a Mi BVS
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XML
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: Chemosphere Año: 2024 Tipo del documento: Article Pais de publicación: Reino Unido