Uranium(VI) complexation with trans-1,2-cyclohexanediaminetetraacetic acid in solution: thermodynamic and structural studies

Le résumé fourni par la source

Interaction between uranium(VI) and aminopolycarboxylic acids could significantly influence the chemical behavior of uranium(VI) in the processing and disposal of nuclear wastes. Trans-1,2-cyclohexanediaminetetraacetic acid (CDTA) is a commonly used aminopolycarboxylic acid, but its complexation with uranium(VI) has not been sufficiently studied. In this study, stability constants of CDTA protonation and U(VI)-CDTA complexes at different temperatures were measured by potentiometry. Their enthalpies and entropies were obtained from van’t Hoff plots. As a result, four U(VI)-CDTA species, UO2(H2CDTA), UO2(HCDTA)-, UO2CDTA2- and UO2(OH)CDTA3-, were identified at pH 3-6 and their coordination modes in solution were demonstrated by thermodynamic studies. The proposed coordination modes of UO2(H2CDTA) and UO2(HCDTA)- in solution differ from the reported crystals; the former is bidentate bonding with one carboxylate and the latter is tridentate bonding with iminodicarboxylate.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.