By harnessing the power of magnetism, researchers have figured out a new way to clean up oil spills.

After the 2010 Gulf of Mexico oil spill, plumes of crude sank to depths in the ocean that were inaccessible to cleanup vessels. Some crude was set on fire in controlled burns before it could reach the shore. Berms were used to protect coastlines.

Compared with these methods, the new technique will be less harmful to the environment and will presumably speed up the overall cleanup process by removing oil from water more efficiently.

Behind the technology is the field of magnetic liquids, or ferrofluids. These are synthetic fluids that contain magnetic nanoparticles that are smaller than the tips of sewing needles. The nanoparticles can be added to water or oils to turn the liquids magnetic.

As any student who has experimented with magnets can attest, opposite poles attract. This principle has been used to separate magnetized crude oil from water by researchers at the Massachusetts Institute of Technology. Their work will be presented at the International Conference on Magnetic Fluids in January, and two patents have been filed.

The technology as it exists could be used on oil skimmers, which are vessels that collect oily water off the ocean. The skimmers are inefficient especially in bad weather, collecting at best 50 percent water and 50 percent oil, Shahriar Khushrushahi from MIT's Department of Electrical Engineering and Computer Science, said in a video. The oily water is stored on board, and the phases may be separated by spinning the mixture at high speed in a centrifuge.

The process is inefficient, however, because the densities of the liquids are so similar; some oil remains suspended in the water, and vice versa.

The researchers envision a more efficient separation by adding nanoparticles to the mixture. The particles would embed in the oil and make the crude flow to large magnets suspended nearby. The oil attaches to the ends of the magnet in globules that can then be removed. The process may have to be repeated a few times to get maximum purity. A video of the process can be seen here.

The technique would be cost-effective because both nanoparticles and magnets are routinely synthesized at economies of scale for various applications.

"I think it [the new technique] would've made a big difference, especially in the early days of the [Gulf of Mexico] spill, by not letting the spill go on for long," Markus Zahn, professor of electrical engineering at MIT, said in a phone interview. "There were no techniques in place for separating oil and water at that point in time."

The collected oil can be cleaned of nanoparticles and sent to a refinery, Zahn said. Minute traces of water would not be a problem during the refining process. The researchers are now building a larger-scale apparatus for testing.

The technique can be used only on board a ship or in other contained spaces because the environmental effects of adding millions of tiny magnets to the ocean may be detrimental.