Who doesn’t love a cellulose story, especially when it could involve cleaning up oil spills? The Feb. 26, 2013 news item on phys.org titled, Airy but thirsty: Ultralight, flexible, fire-resistant carbon nanotube aerogels from bacterial cellulose, highlights some work being done in China,
They can absorb vast amounts of oil or organic compounds, yet they are nearly as light as air: highly porous solids made of a three-dimensional network of carbon nanotubes. In the journal Angewandte Chemie, Chinese scientists have now introduced a simple technique for the production of these ultralight, flexible, fire-resistant aerogels. Their method begins with bacterial cellulose as an inexpensive starting material. Their fibrous lightweights can “suck” organic contaminants from polluted water and could possibly be used as pressure sensors.
The researchers [led by Shu-Hong Yu at the Hefei National Laboratory for Physical Sciences at Micrscale (HFNL), Univeristy of Science and Technology of China] trimmed off small pieces of the tangled cellulose nanofibers. These were freeze-dried and then pyrolyzed at 1300 °C under argon. This converts the cellulose into graphitic carbon. The density decreases but the network structure remains intact. The result is a black, ultralight, mechanically stable aerogel. Because it is porous and highly hydrophobic, it can adsorb organic solvents and oils—up to 106 to 312 times its own weight. It draws oil out of an oil/water mixture with high efficiency and selectivity, leaving behind pure water. This makes the new aerogel an ideal candidate for cleaning up oil spills or sucking up nonpolar industrial pollutants. The absorbed substances can easily be removed from the gel through distillation or combustion, allowing the gel to be used again.
There’s more about the work and its possible applications at physorg.com or, if you have access behind the paywall, here’s a citation and a link to the research article,
Ultralight, Flexible, and Fire-Resistant Carbon Nanofiber Aerogels from Bacterial Cellulose by Zhen-Yu Wu, Chao Li, Dr. Hai-Wei Liang, Prof. Dr. Jia-Fu Chen, Prof. Dr. Shu-Hong Yu. Angewandte Chemie International Edition, Volume 52, Issue 10, pages 2925–2929, March 4, 2013.
Here’s an image which illustrates the aerogels’ ability to suck up an organic solvent and explains some of the excitement,