Interaction of Eu3+ with N,N,N′,N′-tetraoctyl diglycolamide: A time resolved luminescence spectroscopy study

N,N,N',N'-tetraoctyl diglycolamide (TODGA) has been identified as one of the promising extractants for the partitioning of minor actinides from high-level nuclear waste Solutions. Solvent extraction Studies have shown that stoichiometry of the extracted species of EL3+ with TODGA depend on the nature of diluent. Time resolved luminescence spectroscopy (TRLS) has been employed to investigate the complexation of Eu3+ with TODGA under different experimental conditions. The effects of different experimental parameters such as aqueous phase acidity, nature of diluent, and TODGA concentration on the luminescence lifetime of Eu3+ ions have been investigated. The lifetime measurements of the complexed fraction of Eu3+ with TODGA suggested the absence of water molecules in the inner coordination sphere of the metal ion in different solvents. In ethanol-water (60/40%) Mixture, the complexation of Eu3+ with TODGA Under varying ligand-to-metal ratios Suggested the formation of 1:1, 1:2, and 1:3 species, viz., Eu(TODGA)31, Eu(TODGA)(2)(3+), and Eu(TODGA)(3)(3+), respectively. The conditional stability constants log beta(1), log beta(2), and log beta(3) were calculated as 6.1 +/- 0.5. 10.8 +/- 0.7. and 14.3 +/- 0.6, respectively. The nature of diluent did not influence the luminescence Spectra of Eu3+ in the presence of TODGA. (C) 2009 Elsevier B.V. All rights reserved.