Separating oil and water is not supposed to be a challenging task, but when it comes to getting spilled crude oil out of contaminated water, things can get a bit more complicated. Researchers at the Massachusetts Institute of Technology, though, hope that magnets could do the trick where filters and centrifuges have fallen short.
Making magnets
The idea of using magnets to pull metals out of a mixture of materials is hardly unique, but oil does not quite fit the bill as a "metal." That does not mean, however, that researchers cannot force the issue.
"After the BP oil disaster about two years ago, I got the idea that if the oil were magnetic we would be able to remove it with strong magnets and separate it from the water," MIT engineering professor Markus Zahn told Wired.
The idea actually is not as new as it might seem.
MIT News notes that a large amount of engineering research has gone toward turning oil into so-called ferrofluids - a fluid with magnetic particles trapped within it. To create these ferrofluids, researchers can disperse nanoparticles within a mixture of oil and water. These particles will be attracted to the oil, allowing the hydrocarbons to be separated out using magnets.
Magnetic filters
Traditional systems for using magnetics to filter contaminated water would provide two separate channels, one for water and one for oil. Magnets would be used to nudge the magnetized oil into the proper channel.
The problem with this approach, however, is that it can be difficult to ensure that neither water nor oil ends up going down the wrong passage. That means that treated water needs to be run through numerous times in order to thoroughly clean it, while separated oil still has to have water filtered out in order for it to be used.
The MIT team avoids these problems by foregoing the separate passages. Instead, the researchers developed a system with cylindrical magnets standing upright within the stream of water, with the tops just above the surface. Because magnets are strongest at their ends, the treated oil is attracted to exposed tips of these cylinders, where they will form beads primarily composed of oil. The cleaned water will then continue through the system to a storage area, and the trapped oil can be extracted using a type of strengthened magnet arranged in what is known as a Halbach array.
"The process may seem simple," said postdoctoral engineering researcher Shahriar Khushrushahi. "But it is, inherently, supposed to be simple."
Without any moving parts or complicated filtration systems, MIT hopes its approach will prove more effective in live oil cleanups on the open water, where repairs can be difficult.
Oil spills still a concern
While it has been two years since the disastrous Deepwater Horizon oil spill in the Gulf of Mexico, the issue remains very much a concern. Other notable spills have occurred on land in places like Michigan and several parts of Canada, though not to the scale as the BP explosion.
In addition, the recent Hurricane Isaac churned up the waters of the Gulf of Mexico to bring back up to the surface much of the oil still remaining on the ocean floor from the Deepwater Horizon spill.
While recent evidence has suggested that much of the oil spilled in that incident was ultimately consumed by regional bacteria, efforts to clean up the spill could nevertheless prove crucial in preventing environmental damage going forward. What's more, the MIT researchers believe that their new approach will prove capable of producing usable oil more readily than other filtration systems.
