Cadmium removal from aqueous solutions by an emulsion liquid membrane The effect of resistance to mass transfer at the outer oil-water interface

摘要

The removal of cadmium ions from an aqueous solution by an emulsion liquid membrane system is demonstrated, and the parameters of the system are experimentally studied in order to optimize the process. The principal result of the present study is the experimentally based conclusion that the main resistance to mass transfer may lie at the outer oil-water interface. This is shown by demonstrating that the separation process is almost independent of the water to oil phase ratio of the inner emulsion, which controls the inner interfacial area for mass transfer as well as the effective thickness of the oil membrane.