SYNERGISM IN THE SORPTION OF EUROPIUM ON CHROMATOGRAPHIC SUPPORTS IMPREGNATED WITH DICARBOLLIDE ACID AND BIDENTATE PHOSPHORORGANIC EXTRACTANT

Extraction chromatographic supports (XAD-7) impregnated with binary mi xtures of cobalt dicarbollide and one of the two phosphororganic extra ctants (dibutyl-N,N-diethylcarbamoylmethyl phosphonate, DBDECMP, or oc tyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide, (CMPO) were prepared using methanolic solutions of the extractants and subsequent evaporation of methanol at mom temperature. The molar ratios (x) in i somolar series of the two extractants were 0, 0.25, 0.5, 0.75, and 1. The sorbents were used for investigating Eu capture from 0.1 and 1M HN O3 solutions under static conditions (24 hours shaking, 2 cm(3) aqueou s phase with 0.2 g sorbent, Eu initial concentrations 3.10(-9), 0.0001 , 0.001, 0.01 and 0.1M). The sorbents containing mixtures of extractan ts corresponding to the interpolated value x = 0.45 (phosphororg./dica rb.) exhibited the highest values of the distribution ratios of Eu. A synergic effect of three orders of magnitude for low concentrations of Eu was observed. A tentative determination is given of the nature and the equilibrium constants of the chemical reactions assumed.