Synergistic extraction of uranium(VI) by 2-hydroxy-1-naphthaldehyde thiosemicarbazone and several neutral donors

Abstract

Summary The extraction behaviour of U (VI) from an aqueous nitric acid medium employing a 2-hydroxy-1-naphthaldehyde thiosemicarbazone in ethyl acetate has been studied in presence of different neutral donors like trioctyl phosphine oxide (TOPO), dimethyl sulphoxide (DMSO) and trioctyl amine (TOA). The extraction constant (log k ex) for the binary organic phases UO2·A·X (where A=ligand, X=NO3 -1) was found to be 1.976 which is by far the largest value amongst known values for the thiosemicarbazone. The overall equilibrium constant (log K) for the ternary complexes UO2A(NO3)·TOPO, UO2A(NO3)·TOA and UO2A(NO3)·DMSO were estimated to be 6.06, 6.77 and 4.95, respectively. The effect of different diluents on the extraction behaviour has also been studied.