Researchers at Texas Tech University, Lubbock, Texas, have found that unprocessed low-micronaire cotton surpasses other, higher grades of cotton in its ability to absorb oil, making it the most effective cotton-based solution for cleaning up crude oil spills.
The research team, led by Seshadri Ramkumar, Ph.D., manager of the Nonwovens and Advanced Materials Laboratory at Texas Tech's The Institute of Environmental and Human Health (TIEHH), found that one pound of the low-grade cotton can take up more than 30 pounds of crude oil, while repelling water owing to its natural waxiness. The team published its findings in the American Chemical Society journal "Industrial & Engineering Chemistry Research."
"In this region, about 10 percent of the cotton grown in West Texas is low micronaire," Ramkumar said. "It doesn't take a dye well, so it gets discounted. However, because low-micronaire cotton is less mature, it shrinks, and you are able to pack more fiber into a given area. The strength here is that the low-micronaire cotton absorbs the most crude oil," he added, noting that the oil sticks to the surface and is also absorbed into the fiber.
Noting the technological shortfalls seen in the cleanup efforts following the Deepwater Horizon oil spill in 2010, Ron Kendall, director emeritus at TIEHH and special assistant to the president, said the research team's findings are a "breakthrough discovery" that answers the need to improve oil cleanup technology. "It gives us an excellent tool for cleanup of shorelines, animals and ecologically sensitive areas as well as a new technology for booms that can stop oil sheen moving into wetlands. And it's biodegradable," he said. "This is just another added bonus use for low-end Wet texas cotton."
"Our interest was to see how raw cotton straight from the bale picks up the crude oil as well as determining the governing mechanism behind picking up the crude oil," Ramkumar said. "We show through sophisticated testing that low-micronaire cotton is much finer and can pick up more crude oil. And crude oil is very different from refined motor oil. It's very dense and releases toxic vapors. It's not as easy to get picked up. In contrast to synthetic sorbents, raw cotton with its high crude oil sorption capacity and positive environmental footprint make it an ecologically friendly sorbent for oil spill cleanup."
Texas Tech graduate student Vinitkumar Singh performed laboratory experiments using crude oil. Cotton Incorporated, Cary, N.C., and The CH Foundation, Lubbock, provided funding for the research.
