(403a) A Smart Oil Spill Dispersant Formulation for Reduced Environmental Impact and Consumption

The application of chemical dispersants is one of the few feasible response measures for minimizing the impact of a large oil spill at sea. Effective use of dispersants can accelerate oil biodegradation by naturally occurring microorganisms and prevent the oil spill from coming ashore and damaging sensitive coastal ecosystems. However, indiscriminate application of dispersant to subsea and surface oil spills results in a significant amount of dispersant not coming into contact with the oil. The aqueous solubility and miscibility of oil spill dispersants and inevitable sea currents cause dispersant to be washed away and wasted. To compensate for inefficiency, large amounts of dispersants are used resulting in high costs and a large environmental load. For example, an estimated 2.2 million gallons of dispersant were applied to the Gulf of Mexico during the Deepwater Horizon oil spill of 2010. A smart dispersant formulation that microencapsulates the active ingredient of chemical dispersants, a surfactant, in a water-insoluble shell has been developed. In this formulation the surfactant payload is only released when in contact with oil, at which time the shell dissolves in the aromatic compounds present in crude oil and refined petroleum products. The components used in this study were the surfactant, dioctyl sodium sulfosuccinate, and aromatic-soluble polymer, polystyrene. A hardening agent, poly(methyl methacrylate), was added to the surfactant to facilitate mechanical grinding into microparticles. The surfactant microparticles were then fluidized while a polystyrene solution was sprayed onto their surface. Following optimization of spray-coating conditions for maximum encapsulation efficiency, the kinetics of surfactant release from the coated microparticles were studied using representative oil components and simulated sea water. This study demonstrates that novel core-shell surfactant-polymer microparticles, prepared by simplistic and scalable technologies including hardening, grinding, and spray-coating, have significant potential for improving oil spill dispersion. Selective delivery of surfactant directly to an oil spill reduces the amount of surfactant needed for effective dispersion, thus reducing the environmental impact of the surfactant.