The development of an extraction strategy based on EHEHP-type functional ionic liquid for heavy rare earth element separation

To develop sustainable and efficient separation technology for heavy rare earth elements (HREEs), the extraction of Lu(III) and neighboring HREEs using EHEHP type acid-base coupling bifunctional ionic liquid (ABC-BIL) was studied for the first time. Selectivity and stripping performances of the ABC-BIL based system were investigated. Primary mechanism of the ABC-BIL based system was indicated to be ion-association. The EHEHP type ABC-BIL contributes to avoid the saponification wastewater from HEH[EHP]. Higher extractabilities of the ABC-BIL for HREEs, i.e., Ho(III), Y(III), Er(III), Tm(III), Yb(III), and Lu(III), are pronounced advantages of the IL based extracting system than traditional HEH[EHP] system.