Pitt professor creates new filter for crude oil

With the power of cotton and an artificial polymer, a new filter designed by Pitt professor… With the power of cotton and an artificial polymer, a new filter designed by Pitt professor Di Gao looks like it should be marketed by the late Billy Mays.

In a YouTube video, Gao pours a dirty-looking mixture over a single sheet of cotton, leaving sludge-like oil above and water below. The miracle product is no television gimmick, either. Gao’s filter could soon be used to help clean up the massive oil spill devastating the Gulf of Mexico.

The announcement last week about Gao’s work prompted a bit of media attention, which the Pitt researcher partly credits for the progress he has made in marketing his invention. A contractor for BP has contacted Gao since the announcement, and both sides are working to get the new filter technology ready for use in the Gulf.

Gao is still working on determining the best method for employing the filter. He has several ideas for how to use the filter including dragging a trough behind a ship and making a giant bucket to contain the oil.

He said that British Petroleum might also be able to use the filter to help protect coastlines by adding lengths of the polymer-treated cotton to existing booms as a kind of skirt, hanging down in the water and preventing oil from escaping below the surface.

Making the filter seems to be almost as easy as tie-dying. To make his filter, Gao dipped a piece of cotton in the polymer solution, then let it air dry.

The process is not only simple but cheap too. Gao said that it will cost about 10 cents per square foot to manufacture.

Gao and his colleagues have been working on polymers, like the one used in the filter, for almost five years. They started working on the most recent polymer about five months ago, several months before BP’s Deepwater Horizon oil rig exploded in April.

Since that explosion on April 20, as many as 30,000 barrels of oil a day have spilled into the Gulf, prompting a massive effort to contain and clean up the leaking petroleum.

To make the filter, Gao and his team designed a polymer “very uncommon in nature.” The solution is so uncommon because it is both oleophobic and hydrophillic — it repels oil but bonds to water. When applied to cotton, the polymer allows water, but not oil, to pass through.

While Gao’s filter may sound like a miracle cure, it must clear a great deal of scrutiny before hitting Gulf waters.

Two of the organizations involved in the cleanup, BP and the Deepwater Horizon Incident Command — an organization of local, state and federal agencies — have taken in tens of thousands of suggestions for cleaning up the oil since the spill began. Each proposed method undergoes a series of steps designed to find the best workable solutions.

Heidi Feick, a spokeswoman for BP, said that its alternative technology program had taken more than 100,000 suggestions since the spill began and has put each through a four-stage process before approval.

At each stage of the process, a team of engineers evaluates the suggestions to determine if they are effective at cleaning up the oil. Another main consideration is whether the suggestions are economically feasible, Feick said.

The length of BP’s approval process will vary based on the idea, Feick said, and whether it needs EPA approval.

Feick said that until a suggestion makes it through the process, she won’t be able to comment on it.

About 10 percent of the suggestions submitted to BP have dealt with actually stopping the spill, but Feick said that most have dealt with cleanup.

More than 200 of the suggestions have made it to the final stage: testing, Feick said.

“We’ve set up a system to make sure every idea gets looked at,” Feick said.

Gao thinks the uniqueness of his filter could help it clear BP’s hurdles.

Most polymer filters are designed the other way around, Gao said, letting oil through, but not water. That presents problems when cleaning up oil spills in water, Gao said. Even in the worst spills, there will still be much more water than oil, and Gao said the sheer mass of water can prevent conventional filters from being effective.

Gao said that the environmental effects of his filter will be minimal, although they will test the filters’ impact further. The leech rate — the amount of polymer that comes off of the cotton — is very low.

“It’s very strongly bonded to the fabric,” Gao said.

Only a single layer of the polymer molecules is bonded to the cotton, meaning there isn’t much to leech away, Gao said.