Fluorescence studies of metal complexes in synergistic extraction systems combining dibutyl phosphoric acid and tri-n-butyl phosphate

The extraction of lanthanides using a combination of tri-n-butyl phosphate (TBP) and dibutyl phosphoric acid (HDBP) was found to display characteristics of microemulsion aggregates, which may be related to synergistic effects. We studied the extraction of lanthanides and actinides, in our case dysprosium, europium, and uranium, with TBP and HDBP in conjunction with 2D fluorescence spectrometry. The results presented indicate that the coordination environment around the metal ion in the organic phase changes as the ratio between TBP and HDBP changes. This suggests the presence of mixed complexes of M:TBP:HDBP but does not rule out the presence of reverse micelles.