Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

Dr Barbara Armbruster promoted to Worldwide Sales and Marketing Director for XEI Scientific September 27th, 2016

Fighting cancer with sticky nanoparticles September 27th, 2016

Gold nanoparticles conjugated quercetin inhibits epithelial-mesenchymal transition, angiogenesis and invasiveness via EGFR/VEGFR-2 mediated pathway in breast cancer September 27th, 2016

UNAM develops successful nano edible coating which increases life food September 27th, 2016

Possible Futures

Crystalline Fault Lines Provide Pathway for Solar Cell Current: New tomographic AFM imaging technique reveals that microstructural defects, generally thought to be detrimental, actually improve conductivity in cadmium telluride solar cells September 26th, 2016

Researchers at the Catalan Institute of Nanoscience and Nanotechnology show that bending semiconductors generates electricity September 26th, 2016

Chains of nanogold forged with atomic precision September 23rd, 2016

Tattoo therapy could ease chronic disease: Rice-made nanoparticles tested at Baylor College of Medicine may help control autoimmune diseases September 23rd, 2016

Nanotubes/Buckyballs/Fullerenes

Semiconducting inorganic double helix: New flexible semiconductor for electronics, solar technology and photo catalysis September 15th, 2016

World's most powerful X-ray takes a 'sledgehammer' to molecules September 14th, 2016

Researchers design solids that control heat with spinning superatoms: Carnegie Mellon University and Columbia University collaborators discover the cause of vastly different thermal conductivities in superatomic structural analogues September 8th, 2016

For first time, carbon nanotube transistors outperform silicon September 8th, 2016

Announcements

Dr Barbara Armbruster promoted to Worldwide Sales and Marketing Director for XEI Scientific September 27th, 2016

Fighting cancer with sticky nanoparticles September 27th, 2016

Gold nanoparticles conjugated quercetin inhibits epithelial-mesenchymal transition, angiogenesis and invasiveness via EGFR/VEGFR-2 mediated pathway in breast cancer September 27th, 2016

UNAM develops successful nano edible coating which increases life food September 27th, 2016

Military

Tattoo therapy could ease chronic disease: Rice-made nanoparticles tested at Baylor College of Medicine may help control autoimmune diseases September 23rd, 2016

Nano-lipid particles from edible ginger could improve drug delivery for colon cancer, study finds September 8th, 2016

3-D graphene has promise for bio applications: Rice University-led team welds nanoscale sheets to form tough, porous material September 7th, 2016

Nanodiamonds in an instant: Rice University-led team morphs nanotubes into tougher carbon for spacecraft, satellites September 6th, 2016

Environment

Coffee-infused foam removes lead from contaminated water September 21st, 2016

Mathematical nanotoxicoproteomics: Quantitative characterization of effects of multi-walled carbon nanotubes: This research article by Dr. Subhash Basak et al. will be published in Current Computer-Aided Drug Design, Volume 12, 2016 September 2nd, 2016

Nanofur for oil spill cleanup: Materials researchers learn from aquatic ferns: Hairy plant leaves are highly oil-absorbing / publication in bioinspiration & biomimetics / video on absorption capacity August 25th, 2016

Researchers watch catalysts at work August 19th, 2016

Home

New flexible material can make any window 'smart' August 23rd, 2016

Industrial Nanotech, Inc. Provides Shareholder Update August 22nd, 2016

Lucintel identifies and prioritizes opportunities for alumina trihydrate (ATH) fillers in the global composites industry August 3rd, 2016

Industrial Nanotech, Inc. Expands Distribution Network in US and Internationally May 9th, 2016

Textiles/Clothing

Stretchy supercapacitors power wearable electronics August 25th, 2016

Weird, water-oozing material could help quench thirst: Nanorods' behavior first theorized 20 years ago, but not seen until now June 13th, 2016

Programmable materials find strength in molecular repetition May 23rd, 2016

The impact of anti-odor clothing on the environment March 31st, 2016

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