SEPARATION OF COPPER BY LIQUID SURFACTANT MEMBRANES

Liquid surfactant membrane separation of cupric cations from acidic aqueous solution with the liquid ion exchanger di(2-ethylhexyl)phosphoric acid: D2EHPA was studied. The effects on the process of the emulsifier concentration, Span 80, over the range from 0.4 to 1.5% (vol.), of the stirring from 300 to 470 rpm, of the membrane viscosity (polybutadiene addition) from 2.0 cP to 4.3 cP, of the KNO3 concentration in the external solution from 0.0 to 1.8 M, of the pH of that solution from 1.5 to 4.5 and of the initial copper concentration over the range from 0.01 g/1 to 7.5 g/l have been determined. Results are discussed in terms of membrane stability and thickness. A model for copper separation by liquid surfactant membrane is presented based on the multiple diffusion of ion-exchanger molecule between membrane interfaces. The effectiveness of liquid D2EHPA membranes for copper recovery from acidic aqueous solution is demonstrated with better utilization of D2EHPA over a corresponding liquid extraction process. © 1978.