Separation of 90Y from 90Sr by a solvent extraction method using N,N,N′,N′-tetraoctyl diglycolamide (TODGA) as the extractant

The relative extraction efficiency of N,N,N′,N′-tetraoctyldiglycolamide (TODGA) towards Y3+ and Sr2+ was investigated from HNO3 as well as HCl medium. The separation factor (S.F.) values were found to be much higher in HCl medium as compared to those obtained from HNO3 medium. Based on the high separation factor values obtained in the HCl media, a separation method for 90Y from 90Sr (containing 90Y in secular equilibrium) has been developed in the present work. The purity of the separated 90Y was ascertained from its decay profile and half-life measurements. The extracted species was determined to be Y(X)3·3TODGA where X− is the nitrate or the chloride anion. The thermodynamic parameters were also determined and the two phase extraction constants (log Kex) were calculated. The extraction of Y(III) was highly exothermic and entropy destabilized and was equally favourable from both HNO3 medium as well as HCl medium.