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."
[This article was written for Fermilab Today: http://www.fnal.gov/pub/today/]
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