Extraction Studies of Uranium(VI), Plutonium(IV) and Americium(III) from Nitric Acid Using the Bi-functional Carbamoyl Methyl Sulfoxide Ligands

The extraction behavior of new bi-functional ligands containing sulfoxide and amide groups viz. N,N′-dibutyl carbamoyl methyl phenyl sulfoxide (L1) and N,N′-dibutyl carbamoyl methyl benzyl sulfoxide (L2) towards the U(VI), Pu(IV) and Am(III) ions from nitric acid was studied. Both of these extractants showed appreciable extractions for U(VI) and Pu(IV) from 1 to 9.5 M nitric acid concentrations. Am(III) did not show an appreciable extraction under the conditions studied. The species extracted from a nitric acid medium correspond to the compositions of [UO2(NO3)2·2L] and [Pu(NO3)4·2L] for L1 and a mixture of [UO2(NO3)2·2L], [UO2(NO3)2·L] and [Pu(NO3)4·2L] for the L2. The conditional extraction constant (Kex) values for the Pu(IV) with L1 and L2 were estimated for the first time, and found to be 6.21 × 102 and 5.64 × 102 mol−4 dm, respectively.