Abstract

Since the risk of oil spills will never diminish and they continue to be a recurring event, methods to manage them are required to be cost efficient and effective. Dispersants are one of the practical responses to oil spills at sea to break the slick into fine droplets. To reduce toxicity of dispersants in the marine environment and enhance biodegradation of the dispersed oil, biosurfactants can be used instead of chemical surfactants in the dispersant formulations. The objective of this research was to evaluate the capability of the biosurfactant rhamnolipid (JBR425) in dispersing oil slicks and ways to improve its efficiency. At 25C̕ and salinity of 35[per thousand], JBR425 (2%) in saline applied at a dispersant-oil ratio (DOR) of 1:2, could disperse 65% of Brut crude oil into the water without settling, but the percentage drops to 12.5% after 2 min of settling. Different solvents and additives were used to increase its efficiency in terms of percentage dispersion and stabilization of the dispersed oil in water. Starch and cellulose, as natural polymeric additives, were used to increase the stability of the emulsion but they were not effective. (Abstract shortened by UMI.)