Solvent extraction of microamounts of europium and americium into nitrobenzene by using synergistic mixture of hydrogen dicarbollylcobaltate and 1,2-(diphenylphosphino)ethylene dioxide

Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B-) in the presence of 1,2-(diphenylphosphino)ethylene dioxide (DPPEDO, L) has been investigated. The equilibrium data have been explained assuming that the cations HL+, HL2+; ML23+; ML33+ and ML43+ (M3+ = Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It has been found that the stability constants of the corresponding complexes EuLn3+ and AmLn3+, where n = 2, 3, 4 and L is DPPEDO, in water saturated nitrobenzene are comparable.