Group partitioning of minor actinides and rare earths from highly active liquid waste by extraction chromatography utilizing two macroporous silica-based impregnated polymeric composites

Abstract

Through an advanced vacuum sucking technique, two macroporous silica-based N, N, N′, N′-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) and octyl(phenyl)- N, N-diisobutylcarbamoyl-methylphoshine oxide (CMPO) polymeric composites, TODGA/SiO 2-P and CMPO/SiO 2-P, were synthesized by impregnating and immobilizing the chelating agents into the pores of the SiO 2-P particles. To partition long-lived minor actinides (MA(III)), such as Am(III) and Cm(III) from highly active liquid waste (HLW), the loading and elution of 15 typically simulated fission and non-fission products from a 3.0 M HNO 3 were performed. In the first column packed with TODGA/SiO 2-P, the simulated elements were effectively separated into following groups: (1) non-adsorption group, (2) MA– lRE–FPs group, (3) hRE group, and (4) micro quantity of Zr(IV). MA(III) was predicted to flow into the second group along with Nd(III) due to their close adsorption and elution onto TODGA/SiO 2-P. In the second column packed with CMPO/SiO 2-P, after conditioning the acidity in MA– lRE–FPs containing 0.05 M DTPA to 3.0 M HNO 3, it was separated into (1) Sr(II) and Pd(II), (2) MA– mRE, (3) lRE, and (4) Zr(IV). MA(III) was believed to flow into MA– mRE effluent along with Gd(III) because of the similar adsorption towards CMPO/SiO 2-P. In terms of the position of MA(III) appeared, an improved MAREC process for long-lived MA(III) partitioning from HLW was proposed.