Nano zirconium hydroxide gel as a sorbent material for 99Mo/99mTc radioisotope generator

Sorption of Mo(VI) from aqueous solutions onto nano zirconium hydroxide gels was studied using ⁹⁹Mo radiotracer. The acid–base titration curves showed that the prepared nano Zr(OH)₄ gels, Gel #1 and Gel #2, were amphoteric materials with points of zero charge (PZC’s) at pH 2.8 and 3.3, respectively. The highest distribution coefficients of molybdate(VI)-⁹⁹Mo between both gels (Gel #1 and Gel #2) and Cl⁻ media were achieved at pH 2. The maximum sorption capacities of Gel #1 and Gel #2 were found to be 165.7 ± 7.5 and 195.4 ± 8.1 mg Mo/g, respectively. The prepared ⁹⁹Mo/^99mTc chromatographic column generator based on Gel #2 (achieving the higher Mo capacity) showed a good performance; the ^99mTc elution yield was 82.7 ± 2.0%, pH of the eluate ranged from 5 to 6.8, and ⁹⁹Mo breakthrough in the eluted ^99mTc was 0.005 ± 0.002% with a radiochemical purity of 97.3 ± 0.9% (as ^99mTcO₄⁻).