Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Carbon Nanotube Sponges

Abstract:
Tough Water-Repellent Sponges Absorb Oils and Solvents up to 180 Times Their Own Weight

Carbon Nanotube Sponges

China | Posted on November 9th, 2009

Scientists have invented a carbon-based sponge that can soak up organic pollutants, such as oils and solvents, from the surface of water. No water is absorbed and the sponge can then be wrung out and reused, like an ordinary household sponge. Absorbing up to 180 times its own weight in organic matter, the sponge is light and tough and has the potential to dramatically enhance oil spill cleanup.

Professors Anyuan Cao (Peking University) and Dehai Wu (Tsinghua University), who are publishing their breakthrough in Advanced Materials, say "the sponges have new properties that integrate the merits of fragile aerogels with their high surface area [the lowest density solid material known is an aerogel], and conventional soft materials with their robustness and flexibility."

Current commercial absorbents for oil spill recovery and industrial use tend to be based on cellulose or polypropylene. These materials can absorb only up to 20 times their own weight and are impractical for large spills, where dispersants are used. Dispersants allow the oil to become diluted, but it remains in the water. Other materials based on porous oxide-based materials or other polymers can absorb up to twice as much pollutant per weight, but generally need to be heated to remove the organic material. High-temperature heating is not practical on small scales or on ships, and a clear advantage of a squeezable sponge is that the oil can be readily recovered and reused. For other applications including solvent cleanup, the sponges can be heated to remove the pollutant, without affecting the properties of the sponges.

Cao and Wu's sponges are made from interconnected carbon nanotubes;­ tiny, strong and hollow cylinders of interconnected carbon atoms. In this instance the tubes are 30­50 nanometres across and tens to hundreds of micrometers long (a nanometre is 10­9 metres, or one millionth of a millimetre; a micrometre is 1000 times as long). The surface of the tubes is naturally hydrophobic (water-hating), therefore no further modification is needed for the sponges to repel water. At the same time, they love to absorb oil on their surface. As the sponges are over 99% porous or empty, they float on water and there is a lot of room for oil to be absorbed, leading to the extremely high capacity for retention ­ for example, 143 times the sponge's weight for diesel oil and 175 for ethylene glycol.

Lateral thinking was the key to the scientists' breakthrough. A major ambition among carbon nanotube researchers is to look for ways to make large lined-up arrays of the tubes. Cao and Wu, however, searched for a method that would make long tubes that were completely disordered. This randomness allows the tubes to slide past each other, allowing the sponge to be manually reduced in size by 95%, and bent or twisted without breaking (a video showing this is available on www.materialsviews.com/matview/display/en/1220/TEXT). As the sponge is squeezed, any oil or solvent in the cavities and on the surface of the tubes is expelled. To gain the best effect, the sponges first have to be filled with solvent and then compressed gently in a process called densification, but after this they are extremely robust and can be used potentially thousands of times. They swell to recover their original dimensions when exposed to oil or solvent and "a small densified pellet of sponge can quickly remove a spreading diesel oil film with an area up to 800 times that of the sponge", as illustrated in the accompanying figure. This effect occurs even if the sponge is placed at the edge of the spill.

Potential applications reach beyond oil spill recovery. According to Cao, "the nanotube sponges can be used as filters, membranes, or absorbents to remove bacteria or contaminants from liquid or gas. They could also be used as noise-absorption layers in houses, and soldiers might benefit by using these sponges in impact energy absorbing components while adding little weight. Thermally insulated clothing is also possible." Large-scale production is currently being investigated.

"Carbon Nanotube Sponges", X. C. Gui, J. Q. Wei, K. L. Wang, A. Y. Cao, H. W. Zhu. Y. Jia, Q. Shu, D. H. Wu, Advanced Materials, 2009, DOI:10.1002/adma.200902986

This paper is available online on www.materialsviews.com/matview/display/en/1220/TEXT

####

For more information, please click here

Contacts:
Prof. Anyuan Cao:
Department of Advanced Materials Processing Technology and Nanotechnology,
College of Engineering, Peking University,
Beijing 100871, P. R. China
www.coe.pku.edu.cn/subpage.asp?id=1645

Copyright © Wiley-VCH

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Nanotech could rid cattle of ticks, with less collateral damage September 1st, 2015

Scientists 'squeeze' light one particle at a time: A team of scientists have measured a bizarre effect in quantum physics, in which individual particles of light are said to have been 'squeezed' -- an achievement which at least one textbook had written off as hopeless September 1st, 2015

Using ultrathin sheets to discover new class of wrapped shapes: UMass Amherst materials researchers describe a new regime of wrapped shapes August 31st, 2015

New material science research may advance tech tools August 31st, 2015

Possible Futures

Sediment dwelling creatures at risk from nanoparticles in common household products August 13th, 2015

Harris & Harris Group Reports Financial Statements as of June 30, 2015, and Announces a Stock Repurchase Program August 10th, 2015

Molecular trick alters rules of attraction for non-magnetic metals August 5th, 2015

Global Carbon Nanotubes Industry 2015: Acute Market Reports August 4th, 2015

Nanotubes/Buckyballs/Fullerenes

Developing Component Scale Composites Using Nanocarbons August 26th, 2015

Southampton scientists find new way to detect ortho-para conversion in water August 25th, 2015

Revolutionary MIT-Developed Nanotechnology Company Showcases at CAMX in Dallas August 20th, 2015

Engineering a better 'Do: Purdue researchers are learning how August 4th, 2015

Announcements

Nanotech could rid cattle of ticks, with less collateral damage September 1st, 2015

Scientists 'squeeze' light one particle at a time: A team of scientists have measured a bizarre effect in quantum physics, in which individual particles of light are said to have been 'squeezed' -- an achievement which at least one textbook had written off as hopeless September 1st, 2015

An engineered surface unsticks sticky water droplets August 31st, 2015

New material science research may advance tech tools August 31st, 2015

Military

Seeing quantum motion August 30th, 2015

These microscopic fish are 3-D-printed to do more than swim: Researchers demonstrate a novel method to build microscopic robots with complex shapes and functionalities August 26th, 2015

Nanotechnology that will impact the Security & Defense sectors to be discussed at NanoSD2015 conference August 25th, 2015

Industrial Nanotech, Inc. Provides Update On Hospital Project, PCAOB Audit, and New Heat Shield™ Line August 24th, 2015

Environment

Successful boron-doping of graphene nanoribbon August 27th, 2015

Iranian Scientists Utilize Nanomembranes to Purify Wastewater of Olive Oil Plants August 20th, 2015

'Diamonds from the sky' approach turns CO2 into valuable products August 19th, 2015

Sonocatalysts Able to Purify Organic Pollutants of Wastewater August 19th, 2015

Home

Industrial Nanotech, Inc. Provides Update on PCAOB Audited Financials July 27th, 2015

Solar cells in the roof and nanotechnology in the walls June 16th, 2015

Industrial Nanotech, Inc. Continues Global Development Focus on Original Equipment Manufacturer (OEM) Applications: Industrial Nanotech Continues Connecting With Manufacturers Who Seek Out Their Patented Thermal Insulation and Protective Coatings June 11th, 2015

Industrial Nanotech, Inc. Article About the Evolution of Roof Coatings in Durability + Design Magazine June 9th, 2015

Textiles/Clothing

Nanotechnology that will impact the Security & Defense sectors to be discussed at NanoSD2015 conference August 25th, 2015

Possibility to Produce Nanofibers with Controlled Size August 13th, 2015

Engineering a better 'Do: Purdue researchers are learning how August 4th, 2015

Nanoparticles Give Antibacterial Properties to Machine-Woven Carpets August 4th, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic