Corrosion Inhibitor Dispersion Process in Water Visualized through Interaction between Oleic Acid and Decane

Abstract Oil-soluble and water-dispersible corrosion inhibitors are used to mitigate corrosion in pipelines. The performance of corrosion inhibitors has been described mainly in terms of the adsorption of surfactants on metal surfaces. However, the partition of the surfactant from oil to water and its dispersion in water should also significantly affect the corrosion inhibition mechanism of pipelines operating in metal-oil-water systems. Based on this perspective, we investigate the oil droplet dispersion process in the presence of a surfactant. To this end, we measured the inhibition performance, surface tension, and dispersion into the aqueous phase for a simple model inhibitor consisting of oleic acid (OA, surfactant) and decane (C10, oil). The results indicated that the mixing of oil with surfactant increases the amount of dispersion in water by decreasing the interfacial tension between oil and water. The amount of OA molecules dispersing in water was estimated assuming that OA adsorbed on the surface of all C10 droplets. The total absorbed OA molecules increased as the total amount of OA in the system increased. If the total amount was insufficient, the active fraction of OA decreased as the oil/water ratio increased.