Multi-scale structural characterization of Pu(IV) intrinsic colloids by synchrotron SAXS coupled with XAS
Résumé
Anthropogenic activities have released significant amounts of plutonium in the environment
due to the development of nuclear energy for industrial applications, space exploration and
weapon production.|1,2] Both pseudo- and intrinsic plutonium colloids have been described as
potential vectors for the migration of actinides in the environment. Whereas pseudo-colloids
deal with natural inorganic colloids on which Pu has been incorporated or adsorbed, intrinsic
colloids are related to the propensity of tetravalent Pu to hydrolyze and form its own colloid.[1-
3] Predicting the behavior and reactivity of such species in the geosphere is a challenging topic
requiring their thorough characterization in order to provide a better knowledge of their local
structure, morphology, size and interfacial properties. X-ray based techniques appear
particularly relevant to probe the multi-scale properties of Pu colloids. The recent development
of an analytical bench devoted to the quasi-simultaneous analysis of radioactive samples by
small-angle X-ray scattering (SAXS) and X-ray absorption spectroscopy (XAS) on the MARS
beamline of the synchrotron SOLEIL allowed us to screen intrinsic Pu(IV) colloids (Fig. 1).
Two kinds of stable colloidal suspensions prepared by conventional hydrolysis and sonication
of PuO2 powder in pure water (20 kHz, 20 °C, Ar/10%CO atmosphere) were investigated.[4,5]
The non-intrusive synchrotron SAXS/XAS approach described in this work provides in-situ
information, over a large sample volume and directly in the native environment. The approach
appears ideal for Pu colloidal systems and demonstrates that the preparation conditions
strongly influence the multi-scale properties of intrinsic Pu(IV) colloids
Domaines
Chimie inorganiqueOrigine | Fichiers produits par l'(les) auteur(s) |
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