Stability of Prussian blue bound to anion-exchange resin beads for radiocaesium reduction in foodstuffs

Emergency decontamination of foodstuffs may be necessary after an extensive radioactive fallout causing food shortages. Prussian blue bound to spherical inert beads would be suitable for radiocaesium reduction if leaching of Prussian blue components could be minimized. Prussian blue was synthesized by consecutive binding of its constituents to macroreticular anion-exchange resin beads. After various incomplete synthesis cycles (i.e. [Fe(CN)6]4− binding last), the beads (designated RCF1.5, RCF2.5, RCF3.5) leached significantly larger amounts of soluble iron than beads of complete synthesis cycles (Fe3+ binding last; beads designated RCF1, RCF2, RCF3, RCF4). Most of the release from RCF1.5-RCF3.5 beads could be accounted for as [Fe(CN)6]3−, whereas RCF1-RCF4 beads did not leach this substance. Repeated rinsing of RCF3 beads reduced the leach to a minimum. The same extent of leach reduction was also accomplished by treatment with KH2PO4, water-glass, a meat extract or an artificial meat fluid. Treatment with P2O4−7 or P3O5−10 destabilized the RCF3 beads. Properly prepared composite beads after complete cycles of Prussian blue synthesis may be usable for safe reduction of radiocaesium in foodstuffs, at least in meat.