The liquid surfactant membrane separation of copper, cobalt and nickel from multicomponent aqueous solutions

Abstract The separation of the cations of copper(II), cobalt(II) and nickel(II) from their mixed aqueous solutions, by liquid surfactant membranes containing di-(2-ethylhexyl)phosphoric acid (D2EHPA), lauric acid, caprylic acid, LIX-70 and Kelex-100 as ion exchangers and sorbitan monooleate as emulsifier has been studied. The effects of composition and acidity of the external feed solution on the separation of each metal are established. The multistage separation with fresh and reused liquid surfactant membrane was also applied to copper, cobalt and nickel mixed aqueous solution. D2EHPA liquid membranes appeared to be effective for nitrate and chloride systems, while Kelex 100 and LIX 70 membranes allow the separation of the metals studied, even from aqueous sulphate solutions. The process can be strongly competitive with liquid—liquid extraction, in particular in applications to the hydrometallurgical processing of low grade raw materials.