STABILITY OF (W/O) EMULSION DROPS AND WATER PERMEATION THROUGH A LIQUID MEMBRANE

In (W/O)/W dispersions as a liquid surfactant membrane system, the stability of (W/O) emulsion globules and water permeation through the liquid membrane were studied under various operating conditions using Span80 as the emulsifying agent. The membrane stability depends on the surfactant concentration per unit interfacial area below a critical value. It was found that a stable liquid membrane consisting of n-dodecane can be formed from about two layers of surfactant molecules adsorbed at the oil-water interface. The viscosity of the organic solvent had a significant effect on membrane stability. The permeation coefficients of water through the liquid membranes could be correlated with surfactant concentration. Further, entrainment of the external aqueous phase in the (W/0) emulsion droplets was influenced remarkably by the presence of electrolyte in the external solution.