Phase Behavior Study in Systems Containing AEO Nonionic Surfactant, Cosurfactant, Water, and Oil

In this study, phase behavior study was performed for ternary systems containing AEO nonionic surfactant, water and D-limonene as a function of surfactant concentration and temperature. The results in the ternary systems showed that a three phase region containing a middle-phase microemulsion( μE) in equilibrium with excess water and excess oil phase was not found or formed over a very limited small region. On the other hand, addition of butyl diglycol(BDG) and butyl triglycol (BTG) as cosurfactants lowered the temperature for the formation of a three phase region including a middle-phase μE and pro- duced a three phase region over a wide range of temperatures. The solubilization experiments for abietic acid, triolein, and lubricant using three different types of μEs showed that the maximum oil removal was achieved with a water-in-oil(W/O) μE in all cases. Addition of a cosurfactant promoted the solubilization mainly due to a decrease in interfacial tension.