Watch a Biodegradable Chemical Clean Up Spilt Oil

The new creation may make sucking up the toxic substance safer for the environment.

Time is of the essence in the wake of an oil spill. The faster the toxic mess can be cleaned up, the less severe the impacts on animals, the environment, and local livelihoods.

But the methods for reducing the ill effects of that noxious sludge leave plenty to be desired. Currently, most cleanup methods are chemical鈥攅ither dispersants, which break oil up, or , which gather it for easier cleanup. These chemicals鈥 effect on marine life is poorly understood: The most effective commercial herders available contain long chains of silicone聽molecules that break down slowly, so they get the oil out, but leave behind tiny silicone threads that don鈥檛 degrade quickly. Dispersants aren鈥檛 much better鈥, the dispersant used to clean up the BP spill, impeded the respiration of humans and wildlife who came into contact with it.

鈥淭he oil spill is bad enough. We don鈥檛 want to make matters worse by adding something to the marine environment that is also harmful,鈥 says Charles Maldarelli, a professor of chemical engineering at the City College of New York. 鈥淲e want to use something that won鈥檛 stick around.鈥

With that in mind, Maldarelli and others turned to green chemistry, a relatively new approach that relies on molecules found in nature rather than ones synthesized in a lab.聽鈥淣ow that we鈥檙e much more aware of the damage some of those things might inflict on the environment, we want to look at natural molecules that give the same effectiveness but are designed to harmlessly break up,鈥 Maldarelli says. 聽

To design a herder with these properties, Maldarelli and his colleagues first examined the way that commercially available ones work. Herders鈥攁s their name implies鈥攇ather oil. Sprayed in a ring around a thin slick of oil, herders reduce the surface tension between the air and the sea, which allows the buoyant oil to clump at the top of the water so it can be burned or skimmed off the surface. Unlike dispersants, which work best in choppy waters or when oil is flowing from an underwater well, as in the BP oil spill, herders are most useful in calm seas, including ice-clogged waters. When applicable, they are also a greener and more economical solution, since they are sprayed only around the periphery of a spill and allow oil to be taken out of the environment entirely rather than just be broken up.

The researchers鈥 new eco-friendly herder is made primarily of phytol, a smaller molecule that naturally occurs in algae and can be found in trace amounts on the ocean surface. But on its own鈥攅ven in large amounts鈥攑hytol isn鈥檛 active enough to produce the desired surface tension-lowering effect. So the researchers added a small, synthetic, highly polar and positively charged cation, which greatly increases the solution鈥檚 strength. Shortly after being applied to saltwater, the cation naturally separates from the phytol.

To test their creation in the lab, the team poured oil into pans of salt water and encircled the pollutant with either commercial herders or their newly minted natural one, then measured how quickly the oil retracted.

As , they found no difference between the products. 鈥淭hat鈥檚 what we got excited about,鈥 Maldarelli says. 鈥淚t worked as well, if not better, than the top performing synthetic herder.鈥 聽

Maldarelli thinks the formula could be scaled up, producing enough eco-herder to apply the recommended 150 milligrams per square meter of oil, should a spill occur. Before pursuing commercialization, though, the team plans to take a closer look at the cation add-on, putting it through a thorough toxicity screening or possibly replace it altogether. 鈥淲e鈥檇 like to go a step further, making something that鈥檚 composed of two natural products,鈥 Maldarelli says. 聽

Even after the formula is perfected, however, Maldarelli points out that, like all cleanup methods, even the best herder is no silver bullet. 鈥淐hemical herding can鈥檛 get everything, especially if the oil was released near the shore,鈥 he says. 鈥淭he best case scenario is vigilance against oil spills to begin with.鈥澛