Separation of cadmium and zinc by supported liquid membrane using TOPS-99 as mobile carrier

Abstract

The separation of cadmium and zinc from a dilute aqueous sulfate media using supported liquid membrane (SLM) technique has been studied. The microporous polypropylene film Celgard-2400 was used as the solid support for the liquid membrane and TOPS-99 was used as the mobile carrier. The effect of different parameters such as flow rate, pH of feed solution, extractant concentration in membrane phase, acid concentration in strip solution, and Cd(II) and Zn(II) concentration in feed solution on metal ion flux was studied. It was observed that a flow rate of 100 mL/min was sufficient to minimize the resistance due to an aqueous boundary layer at the feed solution membrane interface. The zinc flux increased with an increase of pH from 1.5 to 3.5 and then decreased with a further increase of pH. The cadmium permeation started at a higher pH, i.e., 3.0 and increased with increase of pH up to 3.5 followed by a plateau. Also, with an increase of TOPS-99 concentration in the membrane phase up to 200 mol/m(3), J(Zn) increased and then decreased. The separation factors for cadmium and zinc were calculated at different experimental conditions and are reported.