SYNERGISTIC EXTRACTION OF EU(III) AND AM(III) BY THENOYLTRIFLUOROACETONE AND NEUTRAL DONOR EXTRACTANTS - (CARBAMOYLMETHYL)PHOSPHINE OXIDE AND 2,6-BIS((DIPHENYLPHOSPHINO)METHYL)PYRIDINE N,P,P-TRIOXIDE

Solvent extraction of Eu(III) and Am(III) from weakly acidic solutions with tyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and 2,6-bis((diphenylphosphino)methyl)pyridine N,P,P-trioxide (NOPOPO) in 1,2-dichloroethane was studied on a comparative basis. NOPOPO was found to exhibit unusually high extractability for Eu(III) and Am(III) , probably due to its trifunctional nature, sufficient steric flexibil ity and basicity of the functional groups. Both CMPO and NOPOPO demons trated synergistic effects in extraction of Eu(III) and Am(III) when u sed in combination with thenoyltrifluoroacetone (HTTA). However, the s toichiometry of the extracted species with CMPO/HTTA and NOPOPO/HTTA w as different under similar experimental conditions. The extractant dep endencies of the synergistic extractions suggest that the extracted sp ecies are the adduct complexes, M(ClO4)(TTA)(2)(CMPO)(2) and M(ClO4)(2 )(TTA)(NOPOPO)(2), respectively. It was also observed that CMPO and CM PO/HTTA in dichloroethane extracted Eu(III) and Am(III) equally well, with very similar extraction constants. However, NOPOPO and NOPOPO/HTT A in dichloroethane demonstrated a slight preference for Eu(III) over Am(III), with the extraction constants for Eu(III) more than one order of magnitude higher than that for Am(III).