As part of our efforts to develop efficient extractants for highly alkaline high-level waste at the Savannah River Site, extraction studies of Sm(III) by three types of sulfonamide ligands have been carried out. Aqueous phases of various alkalinity (pH 10 - 14) were used, while dichloromethane was the organic phase. Analysis of the aqueous phases by the Arsenazo-III UV-Vis spectrophotometric method was carried out following stripping of the organic phases with 0.1 M HNO3. The results indicate that all three types of sulfonamides exhibit strong Sm(III) extraction and recovery at pH range of 10-11.5 in the presence of an organic base (triethylamine). A UV-Vis titration study of disulfonamide (DSA-7) with Sm(III) is indicative of 1:1 M/L complexation in solution in accordance with our previously published work with analogous disulfonamides.
