Maria BOLTOEVA1, Guillaume ZANTE1, Abderrazak MASMOUDI1, Virginie GOETZ1, Dominique TRÉBOUET1
1IPHC, Strasbourg, France
Ionic liquids have been widely studied over the last years for metal ion separation and recovery. In solvent extraction, room-temperature ionic liquids can be used in several ways, namely as simple diluents for extractant molecules, extractants or synergic agents. Unique physicochemical properties of ionic liquids such as their high viscosity allow also apply them in membrane separations, in particular in supported ionic liquid membranes (SILM).
The presentation will be focused on the extraction and separation of critical metals such as lanthanides, lithium, cobalt and noble metals. First, we will present the results of the liquid-liquid extraction of metal ions with ionic liquids based on NTf2- (bis(trifluoromethylsulfonyl)imide) anion and cations such as Imidazolium (1-Butyl-3-methylimidazolium) or Phosphonium (Trihexyltetradecylphosphonium). Then, we will consider the metal separation by SILM. The influence of the aqueous phase pH, the effect of the extractant concentration, the initial metal concentration and the synergistic agent concentration on the extraction efficiency and selectivity were studied. The speciation of metals and mechanisms of extraction as well as the advantages and drawbacks of different approaches will be considered.