Wood sponge soaks up oil from water

October 24, 2018, American Chemical Society
Wood sponge soaks up oil from water
Credit: American Chemical Society

Oil spills and industrial discharge can contaminate water with greasy substances. Although it's true that oil and water don't mix, separating and recovering each component can still be challenging. Now, researchers have created sponges made from wood that selectively absorb oil, and then can be squeezed out and used again. They report their results in ACS Nano.

Over the years, scientists have developed numerous techniques to clean up oily water, from gravity separation to burning to bioremediation. But many of these methods suffer from limitations, such as low efficiency, secondary pollution and high cost. More recently, researchers have explored 3-D porous materials, such as aerogels or , based on various building blocks including synthetic polymers, silica or cellulose nanofibers. However, these are often difficult to fabricate, lack mechanical robustness or are made from nonrenewable, nondegradable materials. Xiaoqing Wang and colleagues wanted to develop a sponge made from —a renewable resource—that would absorb oil and tolerate repeated squeezing without structural failure.

The team made the wood sponge by treating natural balsa wood with chemicals that removed lignin and hemicellulose, leaving behind a cellulose skeleton. They then modified this highly porous structure with a hydrophobic coating that attracted oil, but not water. When placed in a mixture of water and silicone oil, the wood sponge removed all of the red-dyed oil, leaving clean water behind. Depending on the oil tested, the sponge absorbed 16 to 41 times its own weight, which is comparable to or better than many other reported absorbents. In addition, the sponge could endure at least 10 cycles of absorption and squeezing. The researchers incorporated the wood sponge into an oil-collecting device in the lab that continuously separated oils from the surface.

Explore further: New wood-metal hybrid for lightweight construction

More information: Hao Guan et al, Highly Compressible Wood Sponges with a Spring-like Lamellar Structure as Effective and Reusable Oil Absorbents, ACS Nano (2018). DOI: 10.1021/acsnano.8b05763

Related Stories

New wood-metal hybrid for lightweight construction

September 4, 2018

Wood foam and metal sponge – can they be combined? That was the question that experts at the Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut WKI delved into in a project entitled "HoMe Foam" – with HoMe ...

Nanocellulose sponges to combat oil pollution

May 6, 2014

A new, absorbable material from Empa wood research could be of assistance in future oil spill accidents: a chemically modified nanocellulose sponge. The light material absorbs the oil spill, remains floating on the surface ...

Large scale preparation method of high quality SWNT sponges

August 24, 2018

In a paper published in Nano, a group of researchers report developing a simple flame-burning method to prepare single-walled carbon nanotube (SWNT) sponges on a large scale. The SWNT sponge has multifunctional properties ...

Why the world needs the humble glass sponge

March 23, 2018

Recent research from the University of Alberta reveals how fishing practices like trawling may be affecting the health of sponges that act like natural water filters.

Recommended for you

Semimetals are high conductors

March 18, 2019

Researchers in China and at UC Davis have measured high conductivity in very thin layers of niobium arsenide, a type of material called a Weyl semimetal. The material has about three times the conductivity of copper at room ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.