Modeling of Leakage in Liquid Surfactant Membrane Systems

Document Type


Publication Date

Fall 1988


The stability of double emulsions or liquid surfactant membranes, an important topic in liquid membrane extraction processes, was investigated. The percentage of liquid membrane leakage which reflects the stability of the liquid surfactant membranes was measured as a function of time using sodium hydroitide as a tracer. Water-in-oil emulsions were prepared with SOLTROL 220, an isoparaffinic solvent, and solvent extracted neutral oils—S100N and S500N. A stochastic model for droplet formation under the conditions of isotropic turbulence was developed. It assumes the presence of complete randomness in the process of emulsification. The mean growth rate obtained from this model is in excellent agreement with microdroplet formation data from the literature. A model for leakage of internal reagent into the bulk phase for liquid membrane systems was derived from the droplet formation model, assuming macrodroplet breakup to be the main mechanism responsible for microdroplet release. The internal reagent was assumed to have negligible diffusivity through the membrane. Experimental data on the leakage of sodium hydroxide into deionized water were found to be in good agreement with the model predictions. The model is quite robust, accounting for apparently different types of behavior observed by a number of investigators.

Publication Title

Chemical Engineering Communications





First Page


Last Page