Ultra porous nanocellulose aerogels as separation medium for mixtures of oil/water liquids
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A novel type of sponge-like material for the separation of mixed oil and water liquids has been prepared by the vapour deposition of hydrophobic silanes on ultra-porous nanocellulose aerogels. To achieve this, a highly porous (>99%) nanocellulose aerogel with high structural flexibility and robustness is first formed by freeze-drying an aqueous dispersion of the nanocellulose. The density, pore size distribution and wetting properties of the aerogel can be tuned by selecting the concentration of the nanocellulose dispersion before freeze-drying. The hydrophobic light- weight aerogels are almost instantly filled with the oil phase when selectively absorbing oil from water, with a capacity to absorb up to 45 times their own weight in oil. The oil can also be drained from the aerogel and the aerogel can then be reused for a second absorption cycle.
KeywordsAbsorption Aerogel Cellulose Desorption Oleophilic Separation Superhydrophobic
The authors thank Wallenberg Wood Science Center for financial support. Professor Lars G. Ödberg is acknowledged for valuable discussions and Magnus Hillergren for professional help with the high speed camera. Joanna Hornatowska at Innvenita AB is acknowledged for the tomography measurements and Innventia AB is thanked for supplying NFC. Dr. Andrei Shchukarev at Umeå University is acknowledged for performing the XPS experiments.
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