Metals are widely used in various areas of human life, and their existence in the environment at high concentrations has become a cause for concern. Metals can enter the human body and disturb the human metabolic system. Therefore, research to recover metals from their matrix both from industrial wastewater and from ores or scraps containing metals is of great importance. One of the separation techniques proposed to overcome those issues involves using supported ionic liquid membranes (SILMs). This chapter summarizes the recovery of metals using SILM. In SILM, an ionic liquid that acts as an extractant is embedded in small pores of a polymer support. The latest type of physical impregnation of ionic liquid, which is the type most commonly used in metal separation, is called polymer inclusion membrane (PIM). PIMs were prepared by casting a solution containing an ionic liquid, a plasticizer and a base polymer to form a thin, flexible and stable film. A PIM including ionic liquids has a similar configuration to SILM, and it is considered to be a kind of SILM. In this chapter, effects on the stability and selectivity in SILM and PIM for metal separation are reviewed.
Part of the book: Ionic Liquids
Although ionic liquids (ILs) have excellent properties, their use as extractants in solvent extraction has not completely overcome the problems encountered when organic solvents are used. In conventional solvent extraction, a hydrophobic IL should be used to establish an IL/water biphasic system to replace the conventional organic solvent with ILs. However, the number of water-immiscible ILs is currently limited, and most contain fluorinated anions which are expensive and environmentally nonbenign. Furthermore, the use of an organic solvent as a diluent agent cannot be avoided because of the very high viscosity of ILs. An IL-based aqueous two-phase system (ATPS) can overcome these drawbacks. This chapter summarizes the use of an IL-based ATPS for the separation of metals used in various areas of human life.
Part of the book: Recent Advances in Ionic Liquids