CMPO Functionalized Task Specific Ionic Liquid For Actinide And Lanthanide Extraction

Abstract:

Among industrial processes, extraction and separation of actinides and lanthanides from nuclear waste is one of the most challenging fields. For this purpose, liquid–liquid extraction procedures using neutral organophosphorus compounds, such as carbamoylmethylphosphine oxides (CMPO), are used in current practice in the TRUEX process. Ionic-liquid phases are suitable extraction solvents for metallic radioactive species in liquid/liquid extraction processes as they show high stability under a and γ irradiations and enhanced safety towards criticality.Several groups reported that replacing dodecane in the TRUEX process by a ‘‘hydrophobic’’ IL significantly enhances the extraction of the metal cation by CMPO.Another very promising approach for metal extraction (and many others applications) lies in the concept of task-specific ionic liquids (TSILs). These compounds, consisting of extracting entities grafted onto the cation of the IL, combine the properties of ILs (e.g., nonvolatility, nonflammability) with those of conventional extracting compounds. Upon grafting complexing substructures onto the organic cation of RTILs, the resulting TSILs behave both as the organic phase and the extracting agent, suppressing the problems encountered through extractant/solvent miscibility and facilitating species extraction and solvent recovery.We report the synthesis of a functionalized ionic liquid based on quaternary ammonium cations bearing a CMPO substructure (N,N-dibutylcarbamoylmethyldiphenylphosphine oxide). TSIL In order to evaluate the extracting properties of the newly synthesized TSIL, the extraction of a number of radioactive elements was investigated. Experimental tests with Am(III), Eu(III) and U(VI) were performed at different acid conditions and different TSIL concentrations.Preliminary studies show that high extraction values can be obtained for U(VI) and Am(III) with the new TSIL. The americium loaded in the RTIL phase could be back extracted by contacting the organic phase with a 6M nitric acid solution.

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