Liquid-liquid extraction of lanthanides into ionic liquids with a multidentate ligand

Shimojo, Kojiro   ; Naganawa, Hirochika  ; Kubota, Fukiko*; Yaita, Tsuyoshi; Suzuki, Shinichi; Goto, Masahiro*

The extraction behavior of lanthanides from aqueous solutions into ionic liquids (ILs) and the stripping test have been investigated with N, N, N', N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) as a ligand. TPEN in ILs shows the extremely high extraction performance for lanthanides compared to that in chloroform. The stripping of lanthanides from ILs into a receiving phase is successfully achieved under acidic conditions. Furthermore, the leaching of TPEN from ILs into the receiving phase is negligible small, although almost all TPEN molecules in chloroform readily leach.