Extraction of Rare Earths in Ionic Liquids Via Competitive Ligand Complexation between TODGA and DTPA

With increasing demand and prospective scarcity of rare earths, the capacity to separate these elements with high selectivity is a critical challenge in hydrometallurgy. We evaluate in this article the capacity of N,N,N',N'-tetra-n-octyl diglycolamide (TODGA) to separate lanthanides in both organic solvent and ionic liquids (ILs) using the holdback reagent diethylenetriaminepentaacetic acid (DTPA) in the aqueous phase. Totally, 10 imidazolium-based ILs with various hydrophobicity were studied herein: [C(n)mim][NTf2] and [C(n)mim][BETI] (n =2,4,6,8,10). In this process, selectivity for light lanthanides was obtained owing to a competitive complexation between TODGA and DTPA.