Influences of Pore and Particle Sizes of CMPO/SiO2-P Adsorbent on Extraction Chromatography Process

Extraction chromatography is promising technology for trivalent minor actinides recovery from spent nuclear fuel. In this study, CMPO-impregnated adsorbents with various pore and particle sizes of SiO 2 particles were prepared, and influences of those properties on the adsorption/elution performances were investigated by batch-wise adsorption experiments and column experiments. Only surface of the particle contributed to adsorption when the pore size is too small. In this system, adsorption/elution kinetics was favorable, whereas adsorption capacity was poor. Broadening in the pore size was revealed to enhance diffusion of mobile phase into the particle, and then elution rate was also improved. Since too large pore size might lead weak mechanical strength, refinement in the pore size considering practical operation condition might be required. Large particle showed fine adsorption performance through batch-wise experiments, but formation of channeling or voids inside the packed bed were observed in the column operation. The voids lead poor breakthrough and elution performances. The particle size had to be smaller than 200 μ m for the extraction chromatography system though large particle is desirable in the respects of remote handling and adsorption performance.