Extraction behavior of Am(III) and Ln(III) with diaryldithiophosphinic acids

Diphenyldithiophosphinic acid (DPDTPI), dichlorophenyldithiophosphinic acid (DCPDTPI), dimethylphenyldithiophosphinic acids (DMPDTPI), di(2,5-dimethylphenyl) dithiophosphinic acid (DDMPDTPI), and di(3,5-dichloro-4-methylphenyl) dithiophosphinic acid (DDCMPDTPI) were synthesized. The extraction of Am(III) and Ln(III) from 0.1 mol/L NaClO4 medium with these diaryldithiophosphinic acids in xylene were investigated. The experimental results show that the order of extraction ability is DDCMPDTPI>DMPDTPI>DPDTPI>DCPDTPI>DDMPDTPI, and extraction selectivity for Am(III) is DCPDTPI>DPDTPI>DDMPDTPI>DMPDTPI>DDCMPDTPI. The obtained maximum separation factors (Am/Eu) are 21, 4.4, 1.8, 1.3 and 1.0 for DCPDTPI, DPDTPI, DDMPDTPI, DMPDTPI and DDCMPDTPI, respectively. The lg D increases with atomic number of lanthanide for 5 extractants. (authors)