Stability of water-in-oil emulsion and its liquid membrane

The effects of water content, surfactant concentration, emulsifying time and velocity on stability of water-in-oil petroleum ether emulsions were studied with demulsification ratio as the standard, while the microscope was used to observe samples of the emulsion directly. In the experiment range, the increases of water content and surfactant concentration were beneficial to the stability of emulsion, and the optimal emulsifying time was 20 min and emulsifying velocity was 4000 r·min-1. The stabilities of water in oil emulsions formed by six different kinds of solvent as oil phases, such as n-hexane, cyclohexane, toluene, o-xylene, petroleum ether and kerosene, were studied and compared. Moreover, on the basis of optimal emulsion factors, leakage and swelling of the water-oil-water liquid membrane were studied. The results showed that leakage was small, less than 3.5 percent, but entrainment swelling was serious, about 20 percent.