The extraction, stripping and formation of third phase of U(VI), Th(IV) and Zr(IV) for tri-isoamyl phosphate/n-dodecane system containing di-isoamyl phosphate

As one of the main radiolysis products of tri-isoamyl phosphate (TiAP) in the spent fuel reprocessing process, di-isoamyl phosphate (DiAP) can lead to a significant deterioration of TiAP in extraction performance. In this context, the effect of DiAP on the extraction and stripping behaviors of U(VI), Th(IV), and Zr(IV) for 1.1 mol/L TiAP/ n -dodecane organic phase was investigated for the first time. It has been shown that DiAP can increase the ability of TiAP to extract metal ions and inhibit the stripping, as well as promote the formation of interfacial deposition. Combined with the results of DLS, FT-IR, 31 P NMR, ESI-MS and elemental analysis, the role of DiAP in the formation of interfacial deposition was also elucidated.