Studies on Separation of Minor Actinides from Lanthanides from High Level Waste by Extraction Chromatography Using 2,6-Bistriazinyl Pyridine

2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine (n-Pr-BTP) was impregnated on XAD-7 resin and the extraction performance of this n-Pr-BTP/XAD-7 resin was investigated for the uptake of Am(III) from acidic nitrate solutions. The uptake behavior of the lanthanides, La(III), Ce(III), Nd(III), Eu(III), and Gd(III), as well as elements such as Ba(II), Fe(III), Mo(VI), Ru(III), Zr(IV), Cs(I), and Sr(II) was also studied in batch experiments. It was found that the resin exhibited significantly high extraction and selectivity for Am(III) over the lanthanides and other elements. Based on the results obtained from batch studies, the separation behavior of Am(III) from Eu(III) was examined by extraction chromatography using a column packed with the n-Pr-BTP/XAD-7 resin. A complete separation between Am(III) and Eu(III) was achieved from aqueous phase containing nitric acid and ammonium nitrate in the column experiment. Based on this result, experiments were performed to investigate the separation of Am(III) from the lanthanides from octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO)-treated high-level waste.