Polymer-Based Filter Successfully Cleans Water, Recovers Oil in Gulf of Mexico Test

A piece of chemically treated cotton cloth is able to separate crude oil from sea water (both from the Gulf of Mexico) completely within seconds by using gravity alone. It can be developed into various effective tools for cleaning up the oil spill in Gulf of Mexico. The treated cloth allows water to path through but not oil. The novel surface chemical treatment method is developed by University of Pittsburgh. (Credit: Still image from video courtesy of YouTube)

In response to the massive oil leak in the Gulf of Mexico, a University of Pittsburgh engineering professor has developed a technique for separating oil from water via a cotton filter coated in a chemical polymer that blocks oil while allowing water to pass through. The researcher reports that the filter was successfully tested off the coast of Louisiana and shown to simultaneously clean water and preserve the oil.

Di Gao, an assistant professor and William Kepler Whiteford Faculty Fellow in the Department of Chemical and Petroleum Engineering in Pitt's Swanson School of Engineering, created his filter as a possible method to help manage the spreading oil slick that resulted from the April 20 explosion of BP's "Deepwater Horizon" drilling platform. Gao has submitted his idea through the Deepwater Horizon Response Web site managed by the consortium of companies and government agencies overseeing the disaster response.

A video of Gao testing his filter with oil and water samples from the Gulf of Mexico spill is available on YouTube at www.youtube.com/watch?v=kfRKjiOXVWE

Gao's filter hinges on a polymer that is both hydrophilic -- it bonds with the hydrogen molecules in water -- and oleophobic, meaning that it repels oil. When the polymer is applied to an ordinary cotton filter, it allows water to pass through but not oil. The filter is produced by submerging the cotton in a liquid solution containing the polymer then drying it in an oven or in open air, Gao explained.

For the massive slick off the U.S. Gulf Coast, Gao envisions large, trough-shaped filters that could be dragged through the water to capture surface oil. The oil could be recovered and stored and the filter reused. Current cleanup methods range from giant containment booms and absorbent skimmers to controlled fires and chemical dispersants with questionable effects on human health and the environment.

Gao focuses his research in the development and application of chemical nanostructures, including liquid-resistant coatings. In 2009, Gao reported in the journal Langmuir his demonstration of a nanoparticle-based solution that can prevent the formation of ice on solid surfaces, from power lines to airport runways and roads