Partial purification of neutron-activation 99Mo from cross-contaminant radionuclides onto potassium nickel hexacyanoferrate(II) column

Preparation and characterization of iron(III) 99Mo-molybdate(VI) gels for the assessment of 99mTc elution performance

New iron(III) 99Mo-molybdate(VI) gels (Fe99Mo) of high Mo content were prepared by the precipitation/filtration method. 99Mo–MoO3 dissolved in NaOH was added to aqueous solutions of Fe(NO3)3 at Mo/Fe mole fractions ~2.21 and 1.99 with continuous stirring at ambient room temperature. Two different Fe99Mo were precipitated from the mixed solutions adjusted at pH 2 and 4.7. The amount of water of hydration increased with the increasing the gel settling time and pH of the mixed solution. The matrices were characterized by radiometric, XRD, SEM, XRF, FT-IR, TGA, and DTA measurements. Small chromatographic columns of 2.0 g Fe99Mo containing ≥800 mg Mo tagged with 740 MBq 99Mo were eluted with 5 mL saline solution. Highly reproducible 99mTc elution indices suitable for preparation of 99Mo/99mTc generators were achieved from generator supported with 0.5 g Al2O3 filter. Elution performance of 99mTc radionuclide was highly dependent on the gel structural properties.

Immobilization of Metal Hexacyanoferrate Ion-Exchangers for the Synthesis of Metal Ion Sorbents--A Mini-Review

Metal hexacyanoferrates are very efficient sorbents for the recovery of alkali and base metal ions (including radionuclides such as Cs). Generally produced by the direct reaction of metal salts with potassium hexacyanoferrate (the precursors), they are characterized by ion-exchange and structural properties that make then particularly selective for Cs(I), Rb(I) and Tl(I) recovery (based on their hydrated ionic radius consistent with the size of the ion-exchanger cage), though they can bind also base metals. The major drawback of these materials is associated to their nanometer or micrometer size that makes them difficult to recover in large-size continuous systems. For this reason many techniques have been designed for immobilizing these ion-exchangers in suitable matrices that can be organic (mainly polymers and biopolymers) or inorganic (mineral supports), carbon-based matrices. This immobilization may proceed by in situ synthesis or by entrapment/encapsulation. This mini-review reports some examples of hybrid materials synthesized for the immobilization of metal hexacyanoferrate, the different conditionings of these composite materials and, briefly, the parameters to take into account for their optimal design and facilitated use.