Highly-Lipophilic Sulfonamide Chelators and Analogs for Actinide Separation from Caustic High Level Waste - 22331

In our continued effort to improve the overall alkaline tank waste processing at the Savannah River Site and develop an advanced one-step extraction process, which enhances the established Next-Generation Caustic-Side Solvent Extraction process (NG-CSSX) with simultaneous separation of Cs, Sr and Actinides (An), we have identified o-mono-sulfonamido-phenols and o-phenylenediamine-derived disulfonamides as highly efficient chelators for Sm(III) (used as surrogate for Am(III)) under alkaline conditions. Prior investigations by our group relied on chlorinated solvents, showing Sm(III) recovery up to 81% at pH 13.0- 13.5 for o-phenylenediamine-derived sulfonamides and greater than 90% at pH = 14.0 for o-mono-sulfonamido-phenols, after just one loading-stripping cycle. Encouraged by these prior results we have now extended our work to highly-lipophilic derivatives and their application in process solvents such as n-dodecane, with substantial Sm(III) extraction and recovery consistently maintained to > 40% levels into these non-polar media, after just one loading-stripping cycle. (authors)