3, CEA Marcoule, Bagnols sur Cèze, , France
2, L2C, Montpellier, , France
Radiotoxic elements constitute a source of pollution from the nuclear industry, for which it is important to anticipate effective processes. Among the elements of high radiotoxicity, 137Cs constitutes a priority since it possesses a long half-life of more than 30 years and it decays to 137mBa presenting a high gamma emission. Liquid solid extraction is a seducing process able to transfer large amounts of Cs from liquid wastes to solid matrices than can be further processed more easily than liquids. However, solid matrices have to present excellent properties in terms of mechanical and chemical resistance in order to be able to withstand hydrodynamic stresses, irradiation damages and aggressive environments.
In this communication, we present in a first part the elaboration, careful characterization and Cs sorption tests of carbon nanotubes papers functionalized with hexaferrocyanate nanoparticles. Two distinct sorption sites were identified on functionalized carbon nanotubes, among which one is highly Cs selective. , A high maximum sorption capacity of about 230 mg.g-1 is determined, including 80 mg.g-1 possessing a Cs selective character1.
In a second part, we present the elaboration and characterization of porous ceramic matrices made of silicon carbide, or silicon oxicarbide. A so-called soft templating approach, involving polymeric templates and polycarbosilane precursors is followed in order to control the porosity in the resulting materials. For example, mesoporous SiC presenting a specific surface area of up 400 m2.g-1 has been obtained.2 These materials can be further functionalized in order to be used as Cs sorption matrices.
1 H. Draouil et al., New Journal of Chemistry, 41(15), 7705-7713 (2017)
2 T. Nardin et al., Materials Letters 185, 424-427 (2016)