Evaluating the Sorption Affinity of Low Specific Activity 99 Mo on Different Metal Oxide Nanoparticles.

⁹⁹Mo/^99mTc generators are mainly produced from ⁹⁹Mo of high specific activity generated from the fission of ²³⁵U. Such a method raises proliferation concerns. Alternative methods suggested the use of low specific activity (LSA) ⁹⁹Mo to produce ^99mTc generators. However, its applicability is limited due to the low adsorptive capacity of conventional adsorbent materials. This study attempts to investigate the effectiveness of some commercial metal oxides nanoparticles as adsorbents for LSA ⁹⁹Mo. In a batch equilibration system, we studied the influence of solution pH (from 1–8), contact time, initial Mo concentration (from 50–500 mg∙L⁻¹), and temperature (from 298–333 K). Moreover, equilibrium isotherms and thermodynamic parameters (changes in free energy ΔG⁰, enthalpy change ΔH⁰, and entropy ΔS⁰) were evaluated. The results showed that the optimum pH of adsorption ranges between 2 and 4, and that the equilibrium was attained within the first two minutes. In addition, the adsorption data fit well with the Freundlich isotherm model. The thermodynamic parameters prove that the adsorption of molybdate ions is spontaneous. Furthermore, some investigated adsorbents showed maximum adsorption capacity ranging from 40 ± 2 to 73 ± 1 mg Mo∙g⁻¹. Therefore, this work demonstrates that the materials used exhibit rapid adsorption reactions with LSA ⁹⁹Mo and higher capacity than conventional alumina (2–20 mg Mo∙g⁻¹). [ABSTRACT FROM AUTHOR]