Nuclear Technology / Volume 165 / Number 2 / February 2009 / Pages 200-208
Technical Paper / Decontamination/decommissioning
We developed a new method for the preparing of a potassium cobalt hexacyanoferrate (PCH)/SiO2 composite as a granulated inorganic adsorbent to remove Cs+ from the radioactive waste solution. The process comprised two steps: The first step was preparing nanoscaled PCH particles, and the second step was stabilizing the PCH particles into the in situ-generated porous silica with aqueous silica sol used as SiO2 source. Granulated composite particles with good rigidity could be successfully prepared with this method. At the same time, the PCH content in the composite could reach 70 wt%, which is one of the highest PCH loads that have been reported.
The PCH particles and composite were analyzed with X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy-dispersive analysis of X-rays, and Brunauer-Emmett-Teller methods. It was indicated by the results that the PCH particles and porous silica were mixed with each other homogeneously in the composite. Adsorption behaviors of the composite upon Cs+ under competition of coexisting ions (H+, Na+, and K+) were studied in batch experiments to determine the distribution coefficient (Kd). The as-fabricated composite exhibited high Cs adsorbing capacity (0.335 meq Cs/g composite) and good Cs+ selectivity from the mixture of competing ions (H+, Na+, and K+). All these characteristics made it a promising material for treating radioactive wastewater.