Data for: Adsorption of strontium and caesium onto an Na-illite and Na illite/Na-smectite mixtures: implementation and application of the multi-site ion-exchange model

Saturation curve of Na-illite vs. pH at I = 0.02 mol/kgw (NaCl) and S/L ratio = 19 g/

Data for: Formation of mixed Eu(III)-CO3-fulvic acid complex: spectroscopic evidence and NICA-Donnan modeling

Isotherm of 10 µM Eu fixed to varying SRFA concentration or free in solution at pH ca. 7 and at equilibrium with total carbonate concentration of 10 m

Data for: Adsorption of strontium and caesium onto an Na-illite and Na illite/Na-smectite mixtures: implementation and application of the multi-site ion-exchange model

Saturation curve of Na-illite vs. pH at I = 0.02 mol/kgw (NaCl) and S/L ratio = 19 g/LTHIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Data for: Formation of mixed Eu(III)-CO3-fulvic acid complex: spectroscopic evidence and NICA-Donnan modeling

Isotherm of 10 µM Eu fixed to varying SRFA concentration or free in solution at pH ca. 7 and at equilibrium with total carbonate concentration of 10 mMTHIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Spéciation aqueuse des lanthanides dans le cycle du combustible et l'environnement

National audienc

Mixed Lanthanide-CO3-Fulvic Complex Spectroscopic Evidence

International audienceThe formation of mixed complexes between lanthanides and actinides(III), complexing inorganic anions, and humic substances is still not completely settled, particularly, the competition, or mixed complex formation, with CO32- [1,2]. To propose answers on this topic, time-resolved laser-induced luminescence spectroscopy (TRLS) experiments in the system Eu(III)-CO3-FA at pH 7 are done, using Suwannee River fulvic acid (SRFA). Starting from former characterization of the Eu-SRFA system [3], the evolution of both the fluorescence spectra and lifetimes of Eu(III) at pH 7 and varying concentrations of carbonate and FA are obtained. With the use of an optic parametric oscillator, several excitation wavelengths (λexc) were used either to excite selectively Eu(III) through the 5L6←7F0 transition (λexc = 394.7 nm), to take advantage of the antenna effect from the SRFA (λexc = 390 nm), or to minimize the excitation of the fulvic complex (λexc = 532 nm). The evolutions of the Eu(III) luminescence spectra from the 5D0→7F0,2 transitions are showing modifications of the assymmetry ratio (area ratio of 5D0→7F2 transition to the 5D0→7F1 transition) that indicates the presence of several species in addition to the EuCO3+ and Eu-FA complexes. The occurence of bi-exponential decay times, with a faster than Eu3+ component, is typical of the occurrence of fulvic complex [4] even in the presence of carbonates. The analyses of the undirect excitation of the Eu-CO3-SRFA systems are used to build the complexation isotherms varying both SRFA or total carbonate concentrations in the framework of the NICA-Donnan modeling of the Eu(III)-SRFA system [3,5]. In view of the restricted pH span, no strict attribution to the different possible types of sites can be done. Different complex formation are considered and discussed. [1] Morgenstern et al. Radiochim. Acta 88, 7-16. [2] Pourret et al. J. Colloid Interface Sci. 305, 25-31. [3] Kouhail et al. (accepted) Environ. Sci. Technol. [4] Reiller & Brevet, Spectrochim. Acta A 75, 629-636 [5] Kinniburgh et al. (1999) Colloids Surf. A 151, 147-166

Adsorption behaviour of Cs+ and Sr2+ onto natural clays towards a predictive modelling

International audienc

Investigation of complexation of thorium by humic acid using chemically immobilised humic acid on silica gel

International audienceTo model the influence of humic substances on the migration of tetra-valent actinides (Pu, Np, U) in and around nuclear waste repositories we have immobilized humic acid on silica gel and investigated Th(IV) complexation on it. It is anticipated that this material might serve as geochemical models of the humate-coated minerals that are likely to be present in the vicinity of the repositories. The binding of Th by the immobilized humic acid was examined at pH 4, 5 and 6 in 0.10 M NaClO4 by batch method. Th(IV)-humate conditional stability constants have been evaluated from data obtained from these experiments by using non-linear regression of binding isotherms. The results have been interpreted in terms of complexes of 11 stoichiometry