Emulsion liquid membrane separation of copper from aqueous solution

Abstract

Equilibrium extraction of copper solution by kerosene in the presence of cation carrier, di(2-ethylhexyl)phosphoric acid (D2EHPA), at room temperature for 8 hours was studied. The extraction equilibrium of copper was found to be 8.20*10-4 dm3/mol. It was found that one mole of copper reacted with two moles of dimeric form of D2EHPA to form a complex in the membrane phase. Batch extraction of copper from aqueous solution by emulsion liquid membrane (ELM) process was also studied. The membrane phase consisted of the cation carrier D2EHPA and the surfactant Span80 which dissolved in kerosene. The internal aqueous phase was HC1 solution. The experiments had been varied to determine the optimum conditions for copper separation. It was found that the optimum pH for the extraction of 100 ppm. of copper in the external phase was 3.0. In the membrane phase, 5%(v/v) Span80 and 10%(v/v) D2EHPA were found satisfactory. External phase optimum concentration of HC1 was 1 N. Optimum agitation speed for extraction was 400 rpm. Under these conditions, more than 99% of copper from aqueous solution in external phase were extracted within 5 minutes. At the final extraction, the concentration of copper in the internal phase was twenty folds greater than that of the external phase. The continuous operation of extraction of copper solution was conducted by using the optimum condition of batch operation. The results of these experiments showed when the volumetric flow rate of feed solution was decreased, the percentages of extraction increased and that more than 90% of copper ions were extracted from feed solution.