Extraction of Eu(III) and Am(III) by 1-phenyl-3-methyl-4-acetylpyrazol-5-one (HPMAP) and tri-n-octylphosphine oxide (TOPO) in a room-temperature ionic liquid

ABSTRACT

Extraction behaviour of trivalent americium and europium was investigated with 1-phenyl-3-methyl-4-acetyl-5-pyrazolone (HPMAP) and tri-n-octylphosphine oxide (TOPO) in a room-temperature ionic liquid, 1-methyl-3-octyl-imidazolium bis(trifluoromethylsulphonyl) imide (C₈mim·Tf₂N). In select cases, comparison was made using xylene, a molecular diluent. For binary extraction studies involving only PMAP, Eu³⁺ was marginally better extracted than Am³⁺ and the species extracted into C₈mim·Tf₂N conformed to species of the type M(PMAP)₃ (where M = Am or Eu). On the other hand, cationic species were extracted for the ternary extraction systems involving HPMAP and TOPO. Luminescence spectroscopic studies suggested no inner-sphere water molecules in the extracted species. The luminescence decay lifetime showed mono-exponentials, suggesting the extraction of single species.

Keywords:

• Complexation
• extraction
• lanthanides
• ionic liquid
• pyrazolone

Acknowledgements

The authors thank Dr P. K. Pujari, Head, Radiochemistry Division, for his keen interest in this work.