Supercritical Fluid Extraction of Thorium and Uranium Ions from Solid and Liquid Materials with Fluorinated .beta.-Diketones and Tributyl Phosphate

A recent report shows that trivalent lanthanide and uranyl ions can be extracted by supercritical CO[sub 2] containing the fluorinated [beta]-diketone, 2,2-dimethyl-6,6,7,7,8,8,8-hyptafluoro-3,5-octanedione (FOD). Extraction and separation of actinides by supercritical fluids are of particular interest today because of potential applications to nuclear waste analysis and management. This paper describes the conditions of extracting thorium and uranium ions from solid and liquid materials by supercritical CO[sub 2] containing different [beta]-diketones. The synergistic extraction of the actinides by mixed ligands involving [beta]-diketones and tributyl phosphate (TBP) in supercritical CO[sub 2] is also reported. Synergistic extraction is another approach to improve the efficiencies of ligands of SFE of actinides. Potential applications of this new extraction technique for the separation of actinides from environmental samples are discussed. The five [beta]-diketones tested for the extraction of uranyl and Th(IV) ions in supercritical carbon dioxide are given as follows: acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, thienoyltrifluoroacetylacetone, and FOD. 12 refs., 5 tabs.