Mesoporous imidazolium functionalized surface functionalized ionosilicas have been investigated as anion exchange materials for the adsorption of oxo-anions in aqueous media. We studied particularly pertechnetate adsorption and could show that solids bearing long chain substituted imidazolium groups are highly efficient anion exchange materials often displaying high distribution coefficients between solid and liquid phases. We observed that the distribution coefficient of pertechnetate is a function of the presence of competing anionic species. As a consequence, our experiments allowed reproducing experimentally Hofmeister's series. However, pertechnetate adsorption on the material can completely be inhibited in the presence of highly fluorinated anions such as bis(trifluoromethylsulfonyl)amide (NTf2). This behaviour indicates a particularly imidazophilic behaviour of these anions, which have a particular importance due to their use in water immiscible ionic liquids. Finally, the adsorption process has been shown to be reversible. This feature is of importance in view of the regeneration of the anion exchange material.
Solubility, migration, and bioavailability of plutonium is lacunar because experimental evidences are missing. We report here on X‐ray Absorption Spectroscopy of plutonium in natural seawater. The observed valence state is +IV and its speciation corresponds to PuO2 type colloids. Furthermore, aging of the solution shows a gradient of ordering from hydroxide colloidal species to more crystalline PuO2 colloids.
Five separation methods by Eichrom column extraction chromatography were developed and implemented for performance control of a PUREX (Plutonium, Uranium Refining by EXtraction) test.Four of them, concerning the separation between actinides, are described in this work. The latest, concerning the separation of actinides from fission products in a main raffinate is described in another article submitted to the same journal.For the production of U, Pu and Np streams following the “main extraction” step in the PUREX process, it is necessary to determine the concentration of the two residual actinides in the third actinide stream:A final separation method was developed to quantify the residual U in a Pu/Np flow for the Np/Pu partitioning step of the PUREX process. This separation is a prerequisite for LXF to eliminate any interference due to Pu and Np when measuring the U concentration.These separation methods necessary upstream from the LXF measurement were applied during the PUREX test in 2005 in ATALANTE (French acronym for “Alpha facilities and analysis laboratories, transuranics and reprocessing research”).
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