Microemulsion systems containing diesel and colza oil as alternative fuels: Phase studies, interfacial tension and solubilization

The study presents results on alternative fuel microemulsions prepared with diesel and diesel–colza oil mixtures. The surfactants employed were Brij 30 and AOT and the cosurfactant was i-butanol. The water solubilization in oil/water/surfactant–cosurfactant (OWSC) microemulsion systems was studied by pseudo-ternary phase diagrams and phase behavior. In the Winsor (W)I ↔ WIII ↔ WII sequence, the phase behavior was correlated with the oil/water interfacial tension (σow), the size of dispersed particles and the oil and water solubilization parameters. The results showed that the single phase area is smaller for Brij 30 than for AOT but larger for anionic–nonionic surfactant mixture. The microemulsion area decreases when NaCl is present in the aqueous phase. In the WIII systems, the values of σow are the lowest, the oil and water solubilization parameters the highest and the dispersed particles have the biggest size. The highest water and oil solubilization parameters are obtained with the anionic–nonionic surfactant mixture and the diesel–colza oil blend. The results show that diesel and diesel–colza oil can be mixed with water to develop fuel for diesel engines.