Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > A greener way to grow carbon nanotubes

Graphic: Christine Daniloff
Graphic: Christine Daniloff

Abstract:
Study suggests new way for manufacturers to minimize environmental impact of carbon nanotube production

By Morgan Bettex, MIT News Office

A greener way to grow carbon nanotubes

Cambridge, MA | Posted on November 11th, 2010

Given their size, strength and electrical properties, carbon nanotubes — tiny, hollow cylinders made of carbon atoms — hold promise for a range of applications in electronics, medicine and other fields. Despite industrial development of nanotubes in recent years, however, very little is known about how they form or the environmental impacts of their manufacture.

It turns out that one process commonly used to produce carbon nanotubes, or CNTs, may release several hundred tons of chemicals, including greenhouse gases and hazardous air pollutants, into the air each year. In a paper published last week on the ACS Nano website, the researchers report that in experiments, removing one step in that process — a step that involves heating carbon-based gases and adding key reactive "ingredients" — reduced emissions of harmful by-products at least tenfold and, in some cases, by a factor of 100. It also cut the amount of energy used in the process by half.

"We were able to do all of this and still have good CNT growth," says Desiree Plata, who led the research between 2007 and 2009 as a doctoral student in MIT's joint program with the Woods Hole Oceanographic Institution. Now a visiting assistant professor in MIT's Departments of Aeronautics and Astronautics and Civil and Environmental Engineering (CEE), Plata collaborated on the paper with several MIT and University of Michigan researchers, including Philip Gschwend, Ford Professor of Engineering in CEE, and John Hart, a mechanical engineering professor at the University of Michigan. The study is part of a long-term effort to change the approach to material development so that environmental chemists work with the young CNT industry to develop methods to prevent or limit undesirable environmental consequences.

In their study, Plata and her colleagues analyzed a common CNT manufacturing process known as catalytic chemical vapor deposition. In this method, manufacturers combine hydrogen with a "feedstock gas," such as methane, carbon monoxide or ethylene. They then heat the combination in a reactor that contains a metal catalyst like nickel or iron, which then forms CNTs. The problem is that once the CNTs form, unreacted compounds (up to 97 percent of the initial feedstock) are often released into the air.

Turning off the heat

In a custom-made laboratory-scale reactor, the researchers heated hydrogen and ethylene, which is commonly used in high-volume CNT manufacturing, and then delivered it to a metal catalyst. They found that more than 40 compounds formed, including greenhouse gases like methane and toxic air pollutants like benzene.

The researchers suspected that not all of those compounds were essential for growing CNTs, and they knew that heating the feedstock gas plays a critical role in creating the dangerous compounds. So they combined unheated ethylene and hydrogen with several of the 40 compounds, one by one, to see which combination of compounds led to the best growth. They observed that certain alkynes, or molecules that have at least two carbon atoms stuck together with three distinct bonds, produced the best growth, while other compounds that are undesirable by-products, such as methane and benzene, did not.

Plata and her colleagues accomplished their dramatic reduction in both harmful emissions and energy consumption by impinging room-temperature alkynes, with ethylene and hydrogen, directly onto the metal catalyst, without heat. They also learned that they could reduce the amount of ethylene and hydrogen used by about 20 and 40 percent, respectively, and still achieve the same rate and quality of CNT growth. Plata says that while the results of lab experiments are hard to generalize, in a market that is expected to reach several billion dollars within several years, these changes could translate into "significant cost savings" for manufacturers.

Industry reaction

Although it's too soon for manufacturers to adopt the method presented in the paper, David Lashmore, vice president and chief technology officer of Concord, N.H.-based Nanocomp Technologies, says the method is something his company is willing to try as it looks for ways to minimize the environmental effects of its production process. "This is of high interest to us and could have a broad impact on our process economics," he says.

Plata points out that the MIT study analyzed only one of several feedstock gases used to make CNTs, and that the same analysis needs to be done for the others. But for her own part, she is now focusing on how CNTs form, trying to determine the precise interaction of the metal catalyst and the hydrocarbons in this process. Knowing the catalyst's role could help researchers manipulate CNTs' formation atom by atom — much more precisely than they can now, she says.

The study was funded by the Woods Hole Oceanographic Institution, the Arunas and Pam Chesonis Ignition Grant via the MIT Earth Systems Initiative and the MIT Martin Society of Fellows for Sustainability, the Nanomanufacturing Program of the National Science Foundation, Lockheed Martin Nanosystems and the University of Michigan Department of Mechanical Engineering and College of Engineering.

####

For more information, please click here

Copyright © MIT

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 Links

Nanocomp Technologies

Related News Press

News and information

SEMATECH to Showcase Innovation and Advances in Manufacturing at SEMICON Japan 2014: SEMATECH experts will share the latest techniques, emerging trends and best practices in advanced manufacturing strategies and methodologies November 26th, 2014

Australian startup creates world’s first 100% cotton hydrophobic T-Shirts November 26th, 2014

The mysterious 'action at a distance' between liquid containers November 26th, 2014

'Giant' charge density disturbances discovered in nanomaterials: Juelich researchers amplify Friedel oscillations in thin metallic films November 26th, 2014

Govt.-Legislation/Regulation/Funding/Policy

Lawrence Livermore researchers develop efficient method to produce nanoporous metals November 25th, 2014

Renishaw receives Queen's Award for spectroscopy developments November 25th, 2014

Vegetable oil ingredient key to destroying gastric disease bacteria: In mice, therapeutic nanoparticles dampen H. pylori bacteria and inflammation that lead to ulcers and gastric cancer November 25th, 2014

Research yields material made of single-atom layers that snap together like Legos November 25th, 2014

Possible Futures

A novel method for identifying the body’s ‘noisiest’ networks November 19th, 2014

Researchers discern the shapes of high-order Brownian motions November 17th, 2014

VDMA Electronics Production Equipment: Growth track for 2014 and 2015 confirmed: Business climate survey shows robust industry sector November 14th, 2014

Open Materials Development Will Be Key for HP's Success in 3D Printing: HP can make a big splash in 3D printing, but it needs to shore up technology claims and avoid the temptation of the razor/razor blade business model in order to flourish November 11th, 2014

Academic/Education

SUNY Poly Student Awarded Fellowship with the U.S. Department of Energy's Postgraduate Research Program: Ph.D. Candidate Accepts Postmaster's Appointment To Conduct Research At Albany NanoTech Complex November 13th, 2014

SUNY Polytechnic Institute Hosts Massive Crowd of More Than 3,000 People Who Attended Community Day Activities Across New York State: CNSE’s ‘NANOvember’ kickoff event highlights New York State’s growing high-tech sector with open house events in Albany, Utica, and Rochester November 3rd, 2014

SUNY Polytechnic Institute Invites the Public to Attend its Popular Statewide 'NANOvember' Series of Outreach and Educational Events October 23rd, 2014

First Canada Excellence Research Chair gets $10 million from the federal government for oilsands research at the University of Calgary: Federal government announces prestigious research chair to study improving oil production efficiency October 19th, 2014

Nanotubes/Buckyballs

Tesla NanoCoatings Increasing Use of SouthWest NanoTechnologies Carbon Nanotubes (CNTs) for its Infrastructure Coatings and Paints: High Quality SMW™ Specialty Multi-wall Carbon Nanotubes Incorporated into Teslan®-brand coatings used by Transportation, Oil and Gas Companies November 19th, 2014

Graphene/nanotube hybrid benefits flexible solar cells: Rice University labs create novel electrode for dye-sensitized cells November 17th, 2014

SouthWest NanoTechnologies to Demonstrate 3D Capacitive Touch Sensor Featuring Transparent, Thermoformed Carbon Nanotube Ink at Printed Electronics USA 2014 (Booth J25) -- “Conductive and Semiconducting Single-Wall Carbon Nanotube Inks” will be Topic of Company Presentation November 10th, 2014

Neural Canals Produced in Iran for Recovery of Sciatica Nerve November 8th, 2014

Announcements

SEMATECH to Showcase Innovation and Advances in Manufacturing at SEMICON Japan 2014: SEMATECH experts will share the latest techniques, emerging trends and best practices in advanced manufacturing strategies and methodologies November 26th, 2014

Australian startup creates world’s first 100% cotton hydrophobic T-Shirts November 26th, 2014

The mysterious 'action at a distance' between liquid containers November 26th, 2014

'Giant' charge density disturbances discovered in nanomaterials: Juelich researchers amplify Friedel oscillations in thin metallic films November 26th, 2014

Environment

Iranian Experts Clean Uranium-Contaminated Water by Nano-Particles November 23rd, 2014

Silver Nanoparticles Produced in Iran from Forest Plants Extract November 20th, 2014

Nano Sorbents Able to Remove Pollutions Caused by Oil Derivatives November 20th, 2014

Application of Nanocomposites in Production of Photocatalysts for Water Treatment November 17th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE