Sorption of macroamounts of the technetium thiourea complex cation by a cation exchange resin was studied in HNO3 and HClO4 solutions as a function of the concentration and reaction time for pertechnetate with thiourea. The distribution ratio reaches
the value of 103 and may be even higher (>104) when sorption proceeds from a solution of the solid complex in dilute perchloric acid. The complex cation is extracted from
0.25–1M HNO3 with solutions of the bis(1,2-dicarbollyl)cobalt(III) anion in nitrobenzene—chloroform (1:1), log D=2.75−2.95 being obtained.
The preconcentration and separation of technetium on cation exchangers from dilute mineral acids would seem to be one field