Experimental investigation was performed on the recovery of silver from aqueous solution by W/o/W emulsion liquid membrane with carrier-mediated counter transport mechanism through batch operation. The carrier reagent in the organic membranes was the liquid ion exchanger, bis (2-ethylhexyl) hydrogen phosphate (D2EHPA). The extraction of silver was an exothermic reaction and the stripping of silver complex was an endothermic reaction. Silver extraction rate was considered as a function of various variables such as temperature of system, concentration of carrier, concentration of surfactant, stirring speed, Ve//Vw ratio and W/O ratio. A general permeation model for the extraction of silver by emulsion liquid membranes was presented in which the internal mass transfer in the W/O emulsion drop, the rates of the formation and decomposition of the complex at the aqueous-organic interface, and the leakage of the internal aqueous phase to the external phase due to the membrane breakup were taken into account. It was shown that the extraction rates could be satisfactorily simulated by the present model.
