The current integrated treatment process for alkaline High-Leel Waste (HLW) at the Savannah River Site (SRS) involves an Actinide Removal Process (ARP) which uses Monosodium Titanate for sorption of strontium and actinides followed by the Next Generation Caustic-Side Solvent Extraction (NG-CSSX) process which removes cesium. The overall aim of this study is to incorporate synthetic ligands as strontium and actinide extractants within the NG-CSSX extraction step thus simplifying the process, making it faster, and possibly reducing the amount of titanate needed in the ARP step. Within this goal exploring the coordination chemistry and extraction properties of these ligands with actinides and lanthanides (as surrogates for lanthanides) will give us insight on the design of future ligands that are fully compatible with the NG-CSSX solvent and can be used in the solvent extraction step. Trisulfonamides and monosulfonamides (Figure) with tunable pKa and soft N-donor binding sites were synthesized for eventual use as additives to the NG-CSSX process. Studies for binding and extractions were performed for lanthanides (mainly Samarium).Synthesized ligands were used to extract Lanthanides from alkaline aqueous media into chlorinated solvents (such as dichloromethane) and the % amount of extracted Ln was obtained by the arsenazo III UV-Vis spectrophotometric method. Structural, spectroscopic, and theoretical methods to characterize the system will be presented.

Trisulfonamide and o-sulfonamidophenol ligands as extractants for trivalent actinides from alkaline high-level waste

2019 Spring National Meeting

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