Sorption of Mo(VI) on zirconium molybdosilicate gel and potential application as a 99Mo/99m Tc generator

Abstract

Sorption of Mo(VI) from aqueous nitrate solutions onto zirconium molybdosilicate (ZrMoSi) gel was studied using 99Mo radiotracer. The acid–base titration curve showed that the prepared ZrMoSi gel was an amphoteric material with the point of zero charge (PZC) at pH 2.5. The highest distribution coefficient (600 mL g–1) of 99Mo(VI) on ZrMoSi from nitrate media was achieved at pH 2.1. The sorption kinetics of 99Mo(VI) onto ZrMoSi obeyed the pseudo-second-order model. The breakthrough sorption capacity of ZrMoSi gel was found to be 4.25 × 10–2 [mmol Mo(VI)] g–1. The prepared 99Mo/99m Tc chromatographic column generator showed a good performance: The 99m Tc elution yield was 87.7%, pH of the eluate ranged from 5.6 to 7.2, and the radionuclidic purity of the eluted 99m Tc was >99.99% with a radiochemical purity of 98.31% (as 99m TcO 4 – ).