Super-Absorbent Material Developed to Clean Oil Spills

Scientists from Drexel University and Deakin University in Australia have developed a material that can absorb up to 33 times its weight in oils and organic solvents. The material—a boron nitride nanosheet—could help mitigate the effects of oil spills and other environmental accidents.

In 2013 Deakin University researchers, led by Professor Ying (Ian) Chen, developed the first stage of the material, boron nitride powder, which had strong absorption capabilities but was inadequate for industrial cleanup uses. "You cannot simply throw powder onto oil; you need to be able to bind that powder into a sponge so that we can soak the oil up and also separate it from water,” Chen says.

Turning the powder into a sponge was an essential step in the process. Researchers from Drexel's College of Engineering helped to study and functionalize the powder, commonly called "white graphite," by forming it into atomically thin sheets that could be made into a sponge.

The nanosheet is made up of flakes that are several nanometers (one billionth of a meter) in thickness with tiny holes. This form enables the nanosheet to increase its surface area per gram to a size equal to around five and a half tennis courts.

Chen says that the material acts much like a sponge to absorb oil, which naturally floats to the water surface, in about 20 minutes. Once a sponge layer fills up, it is collected and replaced with a new sponge until all the oil is removed.

"The mechanochemical technique developed meant it was possible to produce high-concentration stable aqueous colloidal solutions of boron nitride sheets, which could then be transformed into the ultralight porous aerogels and membranes for oil clean-up," says Vadym Mochalin, a research associate professor at Drexel while working on the project.

The Drexel team used computational modeling to help understand the details of how the material was formed. In the process, the team learned that the boron nitride nanosheets are flame resistant—which means they could also find applications in electrical and heat insulation. The research team is now readying its “sponge” to be tested by industry.