Simultaneous removal of copper, nickel and zinc metal ions using bulk liquid membrane system

One of the novel techniques of mixture component separation is an application of liquid membranes. This paper reveals the ability of liquid membrane in simultaneous transport of mixture components in which a liquid membrane (LM) constitutes a separate phase which separates mixture from an internal receiving phase. In the present work, the experiments were performed for determining the distribution coefficient and Cu, Ni and Zn metal ion removal measurements. Metal distribution coefficients were obtained by simply equilibrating an aqueous solution of the metal ions with an organic liquid membrane containing a complexing agent (D2EHPA), in a separating funnel at 25 °C. Initially, to assure mass balance, samples of both the phases were analyzed by an atomic absorption spectrophotometer. Routinely, only the aqueous phase was analyzed. Distribution coefficients were measured over a broad range of metal ion concentration. The separation of metal ions was analyzed for bulk liquid membrane–cylinder in cylinder setup, by varying the source metal ion concentration. Maximum extraction of 98.8% of zinc, 95.8% of copper and 95.0% of nickel metal ion was achieved at the optimum conditions and maximum removal of the metal ions was in the order Zn > Cu > Ni.

Research Highlights
► Simultaneous removal of three metal ions using bulk liquid membrane system.
► Diffusion taking place along with convective mass transfer.
► Solute transport affected by pH difference between the phases.