METAL EXTRACTION WITH LIQUID SURFACTANT MEMBRANES: THE ROLE OF THE EMULSIFYING AGENT.

In order to investigate the role of the emulsifier type in the LSM extraction process, a comparative study of the performance of four different emulsifiers, Span 80 (active ingredient, sorbitan monooleate), Arlacel 83 (active ingredients, sorbitan mono- and di-oleates), Span 85 (active ingredient, sorbitan trioleate), and Brij 72 (active ingredient, polyoxyethylene(2)stearyl ether) in copper extraction systems has been undertaken. The experimental techniques employed included the measurement of interfacial tension, membrane stability (as determined by K** plus transfer from the internal to the external phase), and copper transfer using both LSM and Lewis cell (with a conventional organic phase) systems. The extractant used in this study consisted of a mixture of the separately purified anti-isomers of the reagents LIX65N and LIX63.