Large-scale petroleumspills in aquatic environments commonly occur during the production, transportation, refining and storage of crude oil. This can cause major environmental problems due to the toxicity of many compounds in petroleum to aquatic organisms, birds and humans [1–3]. It has been estimated that petroleum is annually spilled on the surface of the ocean in amounts between 10,000,000 and 20,000,000 tons, whereby a ton of it may cover about 12 km2 of the ocean's surface [4]. Moreover, the toxic volatile constituents of petroleum spills can evaporate and as a consequence, cause atmospheric pollution. Thus, clean-up of petroleum spills from the water surface is an important task.