Removal of copper ions from a waste mine water by a liquid emulsion membrane method

This is a communication on the removal of copper(II) ions from a residual mine water using an emulsified liquid membrane (ELM). The membrane was prepared by dissolving the extractant LIX-860 (a salicylaldoxime), used as a mobile carrier, and Span-80, a surfactant, in kerosene. The ELM allowed an efficient metal transport from the feed solution towards the strip liquor, in experiments carried out in a batch-type stirred tank at 30 °C. A screening factor-type experimental statistical design was developed, which established the variables and their interrelation affecting the studied process. The experimental results and the variance analysis indicated that the statistically significant variables on copper transport through the membrane were the extractant concentration, the stirring time and the stirring speed of the double emulsion. The surfactant concentration range employed in this study adequately stabilized the membrane. However, it did not produce any positive effect on metal extraction. It was observed that the use of an excessively high content of surfactant produced lower metal transport extraction since it gave rise to a higher interfacial resistance. The experimental results reported show the potential for removal of valuable or toxic metals from dilute mine solutions using an extractor based on emulsified liquid membranes.