This article appeared in Fermilab Today on July 30, 2014.
Fermilab physicist Arden Warner revolutionizes oil spill cleanup with magnetizable oil invention. Photo: Hanae Armitage
Four years ago, Fermilab accelerator physicist Arden Warner watched national news of the BP oil spill and found himself frustrated with the cleanup response.
“My wife asked ‘Can you separate oil from water?’ and I said ‘Maybe I could magnetize it!'” Warner recalled. “But that was just something I said. Later that night while I was falling asleep, I thought, you know what, that’s not a bad idea.”
Sleep forgone, Warner began experimenting in his garage. With shavings from his shovel, a splash of engine oil and a refrigerator magnet, Warner witnessed the preliminary success of a concept that could revolutionize the process of oil spill damage control.
Warner has received patent approval on the cleanup method.
The concept is simple: Take iron particles or magnetite dust and add them to oil. It turns out that these particles mix well with oil and form a loose colloidal suspension that floats in water. Mixed with the filings, the suspension is susceptible to magnetic forces. At a barely discernible 2 to 6 microns in size, the particles tend to clump together, and it only takes a sparse dusting for them to bond with the oil. When a magnetic field is applied to the oil and filings, they congeal into a viscous liquid known as a magnetorheological fluid. The fluid’s viscosity allows a magnetic field to pool both filings and oil to a single location, making them easy to remove. (View a 30-second video of the reaction.)
“It doesn’t take long — you add the filings, you pull them out. The entire process is even more efficient with hydrophobic filings. As soon as they hit the oil, they sink in,” said Warner, who works in the Accelerator Division. Hydrophobic filings are those that don’t like to interact with water — think of hydrophobic as water-fearing. “You could essentially have a device that disperses filings and a magnetic conveyor system behind it that picks it up. You don’t need a lot of material.”
Warner tested more than 100 oils, including sweet crude and heavy crude. As it turns out, the crude oils’ natural viscosity makes it fairly easy to magnetize and clear away. Currently, booms, floating devices that corral oil spills, are at best capable of containing the spill; oil removal is an entirely different process. But the iron filings can work in conjunction with an electromagnetic boom to allow tighter constriction and removal of the oil. Using solenoids, metal coils that carry an electrical current, the electromagnetic booms can steer the oil-filing mixture into collector tanks.
Unlike other oil cleanup methods, the magnetized oil technique is far more environmentally sound. There are no harmful chemicals introduced into the ocean — magnetite is a naturally occurring mineral. The filings are added and, briefly after, extracted. While there are some straggling iron particles, the vast majority is removed in one fell, magnetized swoop — the filings can even be dried and reused.
“This technique is more environmentally benign because it’s natural; we’re not adding soaps and chemicals to the ocean,” said Cherri Schmidt, head of Fermilab’s Office of Partnerships and Technology Transfer. “Other ‘cleanup’ techniques disperse the oil and make the droplets smaller or make the oil sink to the bottom. This doesn’t do that.”
Warner’s ideas for potential applications also include wildlife cleanup and the use of chemical sensors. Small devices that “smell” high and low concentrations of oil could be fastened to a motorized electromagnetic boom to direct it to the most oil-contaminated areas.
“I get crazy ideas all the time, but every so often one sticks,” Warner said. “This is one that I think could stick for the benefit of the environment and Fermilab.”
—Hanae Armitage
