LIQUID MEMBRANE OPERATION WITH AID OF MICROEMULSION - SEPARATION OF METAL-IONS

A new liquid membrane operation with the aid of rnicroemulsion was proposed for separating metal ions, using the salinity of the aqueous phase as an external variable for controlling the operation. The operation consists of three sub-operation steps: extraction of metal ion from an aqueous phase to W/O microemulsion phase; settling of these two phases; and separation of the W phase in W/O microemulsion. The system studied was several mono-, di- and trivalent metal ions to be extracted to the n-heptane phase with AOT microemulsion. The extraction process, which was governed by electrostatic interaction between the metal ion and the sulfonate anion of the AOT molecule, was controlled by an external variable, namely the salinity of the aqueous phase. The phase separation is also performed by changing the salinity. The salinity condition for the phase separation was elucidated. The feasibility of this operation was demonstrated, and a method of increasing the selectivity for metal ion separation was studied by focussing on the synergism between the agents with ligand group and AOT. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.