During the 2010 Deepwater Horizon oil spill, nearly 800 million liters of oil were released into the Gulf of Mexico polluting the deep ocean and more than 1600 km of the Gulf’s shoreline. A large amount (7 million liters) of oil dispersant, Corexit EC 9500A, was applied to the spill; as a result, the oil was emulsified into microdroplets that remained suspended in the water column. Even though small droplets biodegrade faster, they can pose significant environmental risks. Microfiltration is the one of the most cost-effective remediation technologies that can remove emulsified oil. The present work is the first study of membrane filtration of Corexit-stabilized crude oil emulsions where properties and filterability of the emulsions in aqueous solutions of different salinities are evaluated. Salinity of the continuous phase was altered by adding MgSO4, NaCl, or a synthetic sea salt mixture. Emulsions were characterized in terms of their droplet size distribution, interfacial tension, and zeta potential. Corexit altered both emulsion stability and the wetting properties of the membranes. Emulsion characterization and constant pressure stirred dead-end filtration tests revealed that salinity affects the stability of emulsions and can enhance microfiltration performance. Almost compete rejection of oil was achieved but was accompanied by a precipitous flux decline. The low values of the steady state permeate flux indicate that microfiltration is suitable as a polishing step that follows an extensive pretreatment by large throughput deoiling unit processes such as hydrocyclonic separation or flotation.
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