Nanosheet material absorbs oil like a sponge

Materials scientists from Deakin University have manufactured a revolutionary material, called a boron nitride nanosheet, that can absorb up to 33 times its weight in oils and organic solvents.

The material, which literally absorbs the oil like a sponge, is the result of support from the Australian Research Council and is now ready to be tested by industry after two years of refinement at Deakin’s Institute for Frontier Materials (IFM). The work has been published in the journal Nature Communications.

According to Alfred Deakin Professor Ying (Ian) Chen, the lead author on the paper, the material is the most exciting advancement in oil spill clean-up technology in decades. “Current methods of cleaning up oil spills are inefficient and unsophisticated, taking too long, causing ongoing and expensive damage, which is why the development of our technology was supported by the Australian Research Council,” he said.

Professor Chen explained that in 2013, when the first stage of the material was developed, it was in a powder form. “This powder had absorption capabilities, but 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,” he noted.

Professor Chen’s co-lead author, IFM scientist Dr Weiwei Lei, said turning the powder into a sponge was a big challenge. The team started with boron nitride powder known as ‘white graphite’ and broke it into atomically thin sheets that were used to make a sponge.

“The groundbreaking material is called a boron nitride nanosheet, which is made up of flakes which are just several nanometres in thickness with tiny holes which can increase its surface area per gram to effectively the size of 5.5 tennis courts,” Dr Lei said.

“The pores in the nanosheet provide the surface area to absorb oils and organic solvents up to 33 times its own weight.”

The Australians cooperated with US researchers from Drexel University and Missouri University of Science and Technology in the development of the nanosheets. Professor Yury Gogotsi from Drexel University said these nanosheets do not burn, can withstand flame and can be used in flexible and transparent electrical and heat insulation, as well as many other applications.

Professor Vadym Mochalin, from Missouri University of Science and Technology, added that it is possible to produce high-concentration stable aqueous colloidal solutions of boron nitride sheets, which can then be transformed into the ultralight porous aerogels and membranes for oil clean-up.

“The use of computational modelling helped us to understand the intimate details of this novel mechanochemical exfoliation process,” he said.

The research team is now ready to have the ‘sponge’ trialled by industry.

Image caption: SEM image of boron nitride aerogel with a density of 20 mg cm^-3.

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