Simultaneous Extraction of Lead, Copper, and Cadmium from Aqueous Solution using Emulsion Liquid Membrane Technique

Abstract

A simultaneous extraction study of lead, copper, and cadmium from diluted aqueous solution through Emulsion Liquid Membrane (ELM) technique was conducted and extensive investigations of the impact    of the pH of the feed phase, homogenizer speed, surfactant (Span 80) and carrier (D2EHPA)           concentrations, and ratio of external to membrane phase on the system stability (breakage) and removal efficiencies of Pb2+, Cu2+,Cd2+ ions were experimentally carried out. Kerosene was used as the membrane and stabilized by Sorbitan monooleate (Span 80) as the emulsifier. Bis-2-Ethylhexyl phosphoric acid (D2EHPA) as an extractant and H2SO4 as a reagent (internal phase) were utilized. Lead, Copper, and Cadmium extraction efficiencies of 100%, 100%, and 98% were obtained respectively under specific operating conditions. The emulsion stability of the system was studied, and breakage of 1.8% under the best operating condition was obtained. High reagent (H2SO4) concentration (0.5 M) maintained the simultaneous extraction of the three heavy metals (lead, copper, and cadmium) and minimizes the probable interaction and competing mechanism between them in the extraction stage.