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

Abstract

Abstract Adsorption behavior of 99Mo(VI) and 99mTc(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 Kd-values for sorption of 99Mo(VI) on (CeW) were obtained over the investigated pH range. 99mTc was adsorbed with much lower Kd-values. The Kd-values were pH dependent. Kd-values of 99Mo-adsorption on AG-2X8 were lower than those on (CeW) and vice versa for 99mTc. 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 99Mo and 99mTc on (CeW) were studied using different eluents. 99Mo remained strongly adsorbed under all conditions whereas 99mTc was easily eluted. Adsorption of some fission products, i.e. 95Zr(IV) and 95Nb(V), in addition to 123mTe(IV) and 75Se(IV), as representatives of their corresponding fission product isotopes, as well as 181Hf, as probable radioactive contaminant was also studied. Solutions of the ionic species of those metals were loaded in mixtures together with 99Mo on (CeW) columns. Strong adsorption of those ionic species and 99Mo on (CeW) was found whereas 99mTc was easily eluted. Different eluents were investigated for eluting 99mTc from 99Mo-adsorbed on (CeW).