Aqueous biphasic separation of Ru-97 and Tc-95,Tc-96 from yttrium

摘要

An aqueous biphasic separation technique has been developed for the separation of Ru-97, a potential candidate radionuclide in nuclear medicine, from its target matrix, yttrium. The extraction of ruthenium and technetium from bulk yttrium has been carried out with 50% (w/v) PEG-4000 and PEG-6000 against 2 M solution of various salts, such as Na-citrate, Na-tartarate, Na-malonate, Na2CO3, NaHSO3, Na2SO4, Na2S2O3, K2HPO4, K3PO4, (NH4)(2)SO4 and 4 M KOH, at room temperature. The influence of the pH of some salt rich phases (e.g., Na-tartarate and (NH4)(2)SO4) on the extraction behavior of Ru-97 and Tc-95,Tc-96 into the PEG rich phase was also studied. In the presence of Na-tartarate, Na-citrate, K2HPO4, K3PO4, KOH, Na2CO3, Na2SO4, Na2SO3 and (NH4)(2)SO4 salt solutions, Ru-97 and Tc-95,Tc-96 were preferentially extracted into the PEG rich phase. In 50% (w/v) PEG-4000-2 M (NH4)(2)SO4 ABS system, 83% of Ru-97 along with 96% of Tc-95,Tc-96 were extracted into the PEG rich phase without any contamination of the yttrium target. Back extraction of Ru-97 into the salt rich phases from the PEG rich phase was also carried out using 2 M salt solutions of K2CO3, Na2S2O3 and 4 M KOH. About 90% back extraction of Ru-97 into the salt rich phases without any contamination of Tc-95,Tc-96 was obtained with 2 M Na2S2O3 salt solution. Dialysis of the PEG rich phase containing Ru-97 along with Tc-95,Tc-96 was also carried out against deionised water to obtain pure Ru-97.