Speaker
Dr
Julie Champion
(Laboratoire SUBATECH)
Description
Polonium is a highly radiotoxic element, whose main hazard comes from ingestion or inhalation. One of polonium’s isotopes, polonium-210 (Po-210) exists naturally from the uranium-238 decay. 20% of the annual effective dose of Po-210 comes from inhalation of uranium and thorium radionuclides and 60 % from ingestion. To illustrate the radiotoxicity of Po-210, one may note that 1 µg of Po-210 emits as many alpha particles as 446 kg of uranium-238. Although Pierre and Marie Curie discovered the polonium (Po) element more than a century ago, physico-chemical properties of this element and its compounds and in particular complexes are still barely known. This can be explained by two main reasons: first, polonium is very rare in nature, being found in uranium ores at approximately a ration of 100 µg/ton. Thus, an adapted cyclotron or a reactor is necessary to produce some of its isotopes. Second, polonium has thirty five known isotopes, all of which are radioactive. However, a better understanding of polonium’s affinity with organic or inorganic ligands is essential to improve techniques of biological decorporation or environmental remediation. In this context, there is a need in designing specific decorporating agent for polonium, having a high affinity for this element at a given oxidation degree. A novel water soluble multidentate “N2S2O2/N4O2” ligand complexing agent was designed and synthesized, as a potential new water soluble - selective chelating agent for possible polonium decorporation. This ligand presents a priori ideal characteristics for polonium complexation, i.e. a platform presenting four soft heteroatoms (N/S) and additional two pendant carboxylic groups to complete the octahedral coordination shell suitable for polonium (IV) complexation. Its affinity for polonium was studied at pH=7.4 using a liquid-liquid extraction methodology. In parallel, theoretical calculations were applied to understand more specifically the nature of the “microscopic” interactions of polonium(IV) with the functional groups of the synthesized ligands.
Primary author
Dr
Julie Champion
(Laboratoire SUBATECH)
Co-authors
Dr
Ali Younes
(Subatech)
Dr
Bandoleme MArcel Mokili
(ARRONAX/Subatech)
Dr
Cyrille Alliot
(ARRONAX/INSERM)
Dr
David Deniaud
(Ceisam)
Dr
Eric REnault
(Ceisam)
Dr
Gilles MOntavon
(SUBATECH)
Dr
Nicolas Galland
(Ceisam)
Dr
Remi MAurice
(SUBATECH)
Dr
Sebastien Gouin
(Ceisam)