Sorption behavior of low specific activity 99Mo on Ti- and Zr-xerogels as an alternative to fission-based 99Mo/99mTc generators

In order to contribute to the sufficient supply of clinical Tc-99m(VII), the sorption behavior of neutron-produced Mo-99(VI) was investigated on synthetized single and binary Ti and Zr xerogels treated at different temperatures, under normal operating conditions. Materials were prepared by the sol-gel method and characterized by several techniques. Sorption batch systems were performed using Mo-99 radiotracer to determine the metallic affinity as a function of pH, and a methodology was developed in order to obtain the maximum capacities by surface saturation, where the Ti-388, TiZr-388 (3:1) and Zr-388 samples showed the most noteworthy sorption behaviors (33.1 +/- 0.34 mg/g at pH similar to 6.0, 31.7 +/- 0.27 mg/g at pH similar to 6.5, and 23.5 +/- 0.61 mg/g at pH similar to 6.8, respectively). The molybdenum-99 sorption behavior was also studied by fitting to the Freundlich and Langmuir models, and all xerogels could be described as heterogeneous materials with favorable Mo-99 sorption properties. Finally, preliminary studies of clinical-scale Mo-99/Tc-99m generators were performed, the results revealed the next maximum Tc-99m elution yield order Ti-388 (89.6 %) > TiZr-388 (3:1) (86.7 %) > Zr-388 (77.7 %).