Emulsion liquid membrane for copper and cadmium removal in Taylor-Couette column

n this study, Emulsion Liquid Membrane (ELM) was used for copper and cadmium removal in Taylor-Couette Column (TCC). ELM is a double emulsion of water/oil/water (W/O/W) system consists of three main phases which are membrane phase, internal phase and external phase, while TCC was used to obtain a better mixing condition with a uniform and relatively low fluid shear to maintain the emulsion stability. The chemicals used in this study are Bis(2-ethylhexyl) phosphate (D2EHPA) as carrier, Span 80 as surfactant, kerosene as diluent and hydrochloric acid (HCl) as internal phase. Meanwhile, copper nitrate (Cu(NO3)2) and cadmium nitrate (Cd(NO3)2) solution were used as the external phase. The extraction of copper was executed in a counter rotating TCC and samples were analyzed using Atomic Absorption Spectrophotometer (AAS) to determine the copper and cadmium concentration in external phase. This research was done to study the mixing of wateroil-water (W/O/W) emulsions in Taylor-Couette flow and to identify the best condition to achieve high copper and cadmium removal using ELM in TCC. The parameters involved are the external phase pH, extraction time and rotational speed of the TCC outer cylinder. It was found that pH 4 was the most optimum pH to achieve the maximum extraction efficiency of copper (92.72%) and cadmium (81.29%). While the highest efficiency for copper was at stirring speed of 200 rpm in 5 minutes (96.38%) and cadmium at 600 rpm in 3 minutes (81.59%).