Studies on 99Mo-99mTc adsorption and elution behaviors using the inorganic sorbent ceric tungstate and conventional organic resins

Adsorption behavior of Mo-99(VI) and Tc-99m(VII) was studied on ceric tungstate (CeW) and compared with the adsorption on the conventional cation and anion exchangers Dowex-50X8 and AG-2X8, respectively. The studies were carried out under static and dynamic conditions. The effect of contact time and pH on the adsorption was investigated under static conditions. High K-d -values for sorption of Mo-99(VI) on (CeW) were obtained over the investigated pH range. Tc-99m was adsorbed with much lower K-d -values. The K-d -values were pH dependent. K-d -values of Mo-99-adsorption on AG-2X8 were lower than those on (CeW) and vice versa for Tc-99m. Ionic species of both elements were not adsorbed on Dowex-50X8, indicating the absence of cationic species and the adsorption of both elements on AG-2X8 and (CeW) as anionic species. The loading and elution behaviors of Mo-99 and Tc-99m on (CeW) were studied using different eluents. Mo-99 remained strongly adsorbed under all conditions whereas Tc-99m was easily eluted. Adsorption of some fission products, i.e. Zr-95(IV) and Nb-95(V), in addition to Te-123m(IV) and Se-75(IV), as representatives of their corresponding fission product isotopes, as well as Hf-181, as probable radioactive contaminant was also studied. Solutions of the ionic species of those metals were loaded in mixtures together with Mo-99 on (CeW) columns. Strong adsorption of those ionic species and Mo-99 on (CeW) was found whereas Tc-99m was easily eluted. Different eluents were investigated for eluting Tc-99m from Mo-99-adsorbed on (CeW).