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Dans le domaine de la séparation sélective pour le traitement et la valorisation des combustibles nucléaires usés, l'extraction liquide-liquide est largement utilisée au niveau industriel. Cependant dans le cadre des technologies nucléaires du futur, des procédés alternatifs de séparation sont recherchés. Notamment la précipitation sélective d'actinides par des tensioactifs cationiques en milieu aqueux (l'extraction liquide-solide étudié par Heckmann et al dans les années 80) apparaît comme une approche intéressante. Le principal avantage de cette technique, comparée à l'extraction liquide-liquide, est lié à la diminution du nombre d'étapes dans le processus comme le lavage du solvant ou la désextraction des métaux. De plus, c'est une technique sans solvant organique ce qui réduit considérablement la quantité de déchets contaminés. Pour ces travaux de thèse, nous avons utilisé des méthodes physico-chimiques pour mieux comprendre l'interaction spécifique entre le cation métallique et le tensioactif cationique. Nous avons tout d'abord analysé l'effet spécifique des contre-ions anioniques (Cl-, NO3-, C2O42-) provenant des acides utilisés; puis nous avons étudié finement l'introduction de cations alcalins monovalents et quelques cations multivalents sélectionnés (Cu2+, Zn2+, UO22+, Fe3+, Nd3+, Eu3+, Th4+) sur l'auto-assemblage et les propriétés structurels du tensioactif en variant les conditions thermodynamiques. Nous en avons conclu que l'adsorption d'un complexe anionique stable du métal, à l'interface des agrégats micellaires, influence fortement les paramètres d'agrégation du tensioactif et détermine ainsi les limites d'utilisation de cette technique de séparation. / In the field of selective separation for recycling of spent nuclear fuel, liquid-liquid extraction processes are widely used (PUREX, DIAMEX …) in industrial scale. In order to guarantee a sustainable nuclear energy for the forthcoming generations, alternative reprocessing techniques are under development. One of them bases on the studies from Heckmann et al in the 80's and consists in selectively precipitating actinides from aqueous waste solutions by cationic surfactants (liquid-solid extraction). This technique has some interesting advantages over liquid-liquid extraction techniques, because several steps are omitted like stripping or solvent washing. Moreover, the amount of waste is decreased considerably, since no contaminated organic solvent is produced. In this thesis, we have carried out a physico-chemical study to understand the specific interactions between the metallic cations with the cationic surfactant. First, we have analysed the specific effect of the different counter-ions (Cl-, NO3-, C2O42-) and then the effect of alkaline cations on the structural properties of the surfactant aggregation in varying thermodynamical conditions. Finally, different multivalent cations (Cu2+, Zn2+, UO22+, Fe3+, Nd3+, Eu3+, Th4+) were considered; we have concluded that depending on the anionic complex of these metals formed in acidic media, we can observe either an adsorption at the micellar interface or not. This adsorption has a large influence of the surfactant aggregation properties and determines the limits of the application in term of ionic strength, temperature and surfactant concentration.

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Pas de résumé en français / The goal of this research was the synthesis and spectroscopic, structural andphysical-chemical characterization of cyclic 6- and 7-membered hydroxamicacids, a tetrahydroxamic calix[4]arene-based tetrapodal receptor, and their metalcomplexes with trivalent and tetravalent metal cations. They were characterizedby several techniques such as 1H and 13C NMR, IR, and mass spectroscopies,single crystal X-ray analysis, and potentiometry. Cyclic hydroxamic acids arefound in a few mix siderophores but their coordination properties were stillunknown. The structural features of metal complexes formed with Fe(III),Ga(III), Ce(IV), Zr(IV), Hf(IV), U(IV) and U(VI) have been investigated both inthe solid state and in solution. The synthesis and complexation studies of anoriginal calix[4]arene-based tetrapodal receptor is described. Reactionparameters for all key steps in the synthetic route have been optimized. Thesingle X-ray crystal analysis of benzyl-protected receptor was obtained.Complexation studies with zirconium(IV) and hafnium(IV) evidenced theformation of two metal two ligand complexes rather than 1:1 species, whichwere shown to interact in solution with a third alkali cation

<p>U doktorskoj disertaciji evaluirani su interkorelacioni rezultati odnosa ključnih fizičko-hemijskih parametara i katjona metala u površinskoj vodi Dunava, Tise (na po tri selektovana reprezentativna lokaliteta) i kanala Dunav-Tisa-Dunav (na dva lokaliteta). U<br />Kanalu Dunav-Tisa-Dunav praćene su i rezidualne katjonske koncentracije metala u sedimentu. Na osnovu podataka prisutnosti katjona metala u heterogenom sistemu tečno/čvrsto izračunate su po prvi put konstante podeonih procesa za ispitivane katjone metala. Primenom multivarijantnih statističkih metoda analizirani su korelacioni odnosi između ključnih fizičko-hemijskih parametara i koncentracionih nivoa rezidula katjona teških, lakih i semimetala. Faktorskom analizom (PCA) i klaster analizom sa dendogramima tumačeni, analizirani i diskutovani su dobijeni rezultati. Za optimalnog uočavanja korelacionih odnosa primenjeno je unapređeno rangiranje određenih skupova podataka (interkorelacije ključnih fizičko-hemijskih parametara i rezidua katjona metala) i grafički prikazanih Haseovih dijagrama primenom DART softvera (Decision Analysis by Ranking Techniques) za definisani model procene uticaja raspodele katjona toksičnih metala u heterogenom sistemu tečno/čvrsto na kvalitet površinskih voda.</p> / <p>In the doctoral thesis are evaluated inter correlational results of key physicochemical parameters and metal cations in surface water of Danube, Tisa (on three selected representative sampling points) and canal Danube-Tisa-Danube (on two sampling sites). In the canal Danube-Tisa-Danube are also followed residual metal cations concentrations in sediment. Based on metal cations presence data in heterogeneous system liquid/solid for the first time partitioning processes constants are calculated for<br />selected metal cations. Appling multivariate statistical methods correlations between key physicochemical parameters and concentration levels of residual heavy, light and semimetals cations are analysed. Using factorial analyse (PCA) and cluster analyse with dendograms obtained results were interpreted, analysed and discussed. For optimal comprehension of correlations, advanced method ranking of finite order sets is applied (inter correlations key physicochemical parameters and residual metal cations) and graphically shown Hasse diagrams obtained by DART software (Decision Analysis by Ranking Techniques) for defined impact assessment model of toxic metal cations partitioning in heterogeneous system liquid/solid for surface water quality.</p>

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