Explore the Impact of Surfactant Type on the Stability and Separation Efficiency of Oil–Water Emulsions of Real Wastewater from Al-Basrah Crude Oil Using Microbubble Air Flotation

Among several separation processes, air flotation is distinguished as a remarkably high potential separation process related to its high separation efficiency and throughput, energy-efficient, simple process, cost-effective, applicability to a wide range of oily wastewater, and no by-products. The current study aimed to investigate the effect of the type and concentration of surfactant on the stability of oil-water emulsion and the efficiency of the separation process. For this purpose, three types of surfactant were used (anionic SDS, mixed nonionic Span 85/Tween 80, and cationic CTAB). The results demonstrated that the Span 85/Tween 80 surfactant has the best stability, and it increases with the surfactant concentration augmentation. The removal efficiency with CTAB surfactant reached approximately 95% at a concentration of 0.3% and decreased by increasing the surfactant concentration. The mean diameter of bubbles generated in the emulsion with CTAB surfactant was 71 µm, which was lower than that obtained with the other two surfactants.