Al-Qadisiyah Journal for Engineering Sciences

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.

Abstract A study was carried out to remove cadmium ions from a hydrochloric medium at a concentration of 100 ppm using the emulsified liquid membrane (ELM) technique. Emphasis was placed on assessing process parameters and their effect on changing the concentration of cadmium ions in the hydrochloric solution. To study the performance characteristics of the process, Taguchi method was used with analyzing of signal/noise ratio. Five parameters that affect performance such as (pH of the external phase (1-4), surfactant concentration in the organic layer (4% -10% v / v), carrier concentration in the organic layer (4% -10%  v / v), speed of  Emulsification (5800-24000) rpm and emulsion volume ratio / outer phase ratio (Eml./Ext ratio) was studied, taking into account the change in the concentration of cadmium ions in the external phase. To obtain the lowest concentration of cadmium ions in the external stage, the values ​​of the optimum parameters were: pH = 3, Surfactant conc. = 4%, Carrier conc. = 8% emulsification speed = 19700 rpm, and Eml./Ext.  ratio = 18%. Results of the present work suggested that Eml./Ext. ratio had a major effect on the concentration change, followed by a pH in the outer phase,  the emulsification velocity,  carrier concentration, and the surfactant concentration respectively.