Magnetophoresis of Iron Oxide Nanoparticles for Oil Recovery from Emulsions

Oil-in-water emulsions pose a serious pollution problem which entail a difficult and expensive clean up and separation. In the natural environment, born out of oil spills in a turbulent environment, the resulting oil-in-water emulsions have a tendency to persist, endangering wildlife and ecosystems. In industrial plants, oil-in-water emulsions from an oil pipeline leakage can clog pipework and downstream distillation columns. Traditional methods to remove oil spill from water include containment and skimming, in situ burning, and chemical and biological dispersants. However, these approaches target mainly the oil layer on the water surface instead of emulsified oil spheres, and are often labor-intensive and environmentally harmful. A novel and efficient method to recycle oil from oil-in-water emulsions utilizing oleylamine-capped iron oxide nanoparticles has been developed. Fe3O4 nanoparticles were synthesized by the reductive thermal decomposition of iron (III) acetylacetonate in benzyl ether andoleylamine, washed with ethanol and re-suspended in toluene for use and storage. Suspensions of Fe3O4 nanoparticles in toluene were shown to diffuse through the oil phase in oil-in-water emulsions of different oil contents, after which an external magnet was used to assess the efficiency of oil removal. Overall, the use of iron oxide nanoparticles is a promising method to remove oil from oil-in-water emulsions by making oil droplets magnetically active.