We describe an original process for the treatment of low level activity radioactive liquid wastes. It deals with the electrochemical preparation of three polyacrylate polymers: polyacrylamide (PAam), polyacrylamidoglycolic acid (PAAG), polyacrylamidomethylpropanesulfonic acid (PAMPS) which are capable of complexing uranyl ions.We have demonstrated the complexation of uranyl by FT-IR and UV-Visible spectroscopy. All these complexes are soluble in water and we insolubilize in turn the complexes by crosslinking or by neutralization of positively charged complexes by the addition of polyanions to the medium. We have then done dynamic and static leaching tests on these insoluble complexes.

Branched polyethyleneimine (PEI) was sulfonated by reaction with chloropropanesulfonylchloride and phosphonated by reaction with phosphorous acid and formaldehyde. The accordingly formed polyanions were used as doping agents for polypyrrole (PPy). The amount of doping polyanions into thin films of PPy was measured by Rutherford back-scattering. These films were tested for their capacity to extract uranyl ions from liquid wastes of low level activity. The uranium content was determined by neutron activation analysis, autoradiography, and gravimetry of uranium oxide after calcination. The resistance against static and dynamic leachings was also estimated.

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Polymer composites consisting of polypyrrole doped by uranyl complexing polyanions [i.e., poly(2‐acrylamidoglycolic acid) and poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid)] were electrochemically synthesized. Bulk material and thin layers strongly adhering to inert supporting electrodes were prepared. These composites were used to precipitate uranyl ions from simulated radioactive wastes. Among different experimental techniques used for the analysis of uranium immobilized in the composites, the Rutherford backscattering of α particles proved efficient in thin layers. Leaching tests confirmed the persistence of the uranium complexation in the solid composites. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1230–1239, 2000

We propose a new fully aqueous electrochemical method for the preparation of high resolution alpha sources. Thin films of polypyrrole (PPy) are prepared by anodic electropolymerization, starting from aqueous solutions of the pyrrole monomer and an anionic polyelectrolyte which is able to complex actinide and play the role of PPy doping agent: polyacrylamidoglycolic acid (PAGA). These thin films can be prepared on various electrodes: stainless steel, platinum, glassy carbon and polyethylene doped by carbon-black. Peeling tests revealed their strong adhesion on stainless steel electrode. Alpha sources were prepared by simple immersion in actinide containing solutions. This easy process results in alpha sources with outstanding energy resolution (FWHM: around 9 keV for various isotopes).

3-(Triethoxysilyl)propylacrylamide monomer was synthesized for the first time and then copolymerized with acrylamide (Aam), allyltriethoxysilane (TEA) or 3-(triethoxysilyl)propylacrylate (TMPAac). These three silylated copolymers were investigated as uranyl complexing agents. In another experiment, the copolymers were processed with tetraethylorthosilicate (TEOS) following a sol-gel process to prepare new microporous gels suited for solid-liquid uranium extraction from liquid wastes. The gels were prepared with uranyl as imprinted gels and without uranyl ions in solution to obtain non-imprinted gels. The effect on the uranyl binding capacities of the gels was studied. The imprinted gels were also dipped in ternary solutions of thorium, lanthanum and uranium. Selectivity toward uranyl was observed for uranyl imprinted gels. The stability of the different matrices against dynamic leaching and gamma irradiation was also studied.