ランタノイド相互分離に有効なリン酸エステルを用いて配位高分子を合成し，その中心金属であるランタノイドイオン（Ln^3＋）と他のLn^3＋との交換反応の特性を明らかにした。低濃度のランタノイド溶液では，溶媒抽出と同程度の選択性を実現できた。反応時間は遅いが，有機溶媒を用いないという長所がある。一方で，高濃度のランタノイド溶液では，イオン交換選択性は原子番号順にならず，もともと配位高分子骨格を形成していたLn^3＋よりも約7％小さいサイズのイオンが最大の選択性を示した。金属－配位子間の静電力だけでなく，配位高分子骨格に対するイオンサイズの適合性が関与している可能性が示唆され，溶媒抽出とも従来の無機イオン交換体および有機イオン交換体とも全く異なる選択性の発現に成功したと言える。

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 SiO₂ 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 μm for the extraction chromatography system though large particle is desirable in the respects of remote handling and adsorption performance.