Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers study how to make nanomaterial industry environmentally sustainable

17.03.2005


Transmission electron microscopy shows nano-sized particles that form when fullerenes clump together in water. Research is showing what factors affect particle size. Image Courtesy of John Fortner


Transmission electron microscopy shows nano-sized particles that form when fullerenes clump together in water. Research is showing what factors affect particle size. Image Courtesy of John Fortner


Research into making the emerging nanomaterial industry environmentally sustainable is showing promise in a preliminary engineering study conducted at the Georgia Institute of Technology and Rice University.

Under the auspices of the Rice University Center for Biological and Environmental Nanotechnology (CBEN) funded by the National Science Foundation (NSF), researchers have been investigating the potential environmental impact of nanomaterial waste. Specifically, they want to know if they can predict the fate and transport of nanomaterial waste in natural systems, and whether nanomaterials will behave the same as common environmental pollutants. In addition, they want to determine if nanomaterials can be treated before they enter the environment to minimize impact.

Previous research provided information on how structures such as fullerenes clump together in water to form larger particles. This study is the first to show what factors affect the size of these aggregate particles.



Researchers picked fullerenes, molecules composed of 60 carbon atoms, as their model carbon-based nanomaterial. Fullerenes have a potentially broad range of applications, including their use in pharmaceuticals, as lubricants, as semiconductors and in energy conversion. Mass commercial production of fullerenes may get under way internationally in just two years.

"This research is providing the information to make practices sustainable when fullerene production comes on line," said John Fortner, a Georgia Tech research scientist and Rice University Ph.D. student. "It’s our goal to minimize environmental impact in contrast to the pollution caused in the past by, for example, dry cleaning industry practices.

"It is a new thing to have research funding to look at a material’s potential as a pollutant, how to minimize it’s environmental impact and make the industry sustainable," Fortner added. "It’s really the right thing to do. You know, ’An ounce of prevention is worth a pound of cure.’"

Fortner will present findings of the research team March 16 at the American Chemical Society’s 229th national meeting in San Diego, Calif. The team includes Joe Hughes, chair of the Georgia Tech School of Civil and Environmental Engineering and a former Rice University professor.

Though much is known about fullerenes, little is known about their fate when released into the environment because they have not been produced on an industrial scale. For now, the U.S. Occupational Safety and Health Administration (OSHA) calls for handling fullerenes in the same way as carbon black, which is similar to graphite and very different in properties from fullerenes – in particular the C60 "buckyball" carbon molecules that Fortner and his colleagues are studying.

"Fullerenes are virtually insoluble in water, yet most biological and environmental systems are based around water," Fortner noted. "Researchers thought fullerenes couldn’t be transported by water because they are so hydrophobic. We thought they would simply stick to soil or other organic material. But research shows this is actually not the case. When fullerenes, such as C60, come in contact with water, they form aggregates at the nanoscale. We call it nano-C60."

In their study, Fortner and his colleagues devised several novel applications of imaging techniques to characterize the physical and chemical formation of nano-C60 particles in water mixed with the organic solvent THF. Using cryoTEM (transmission electron microscopy), researchers froze samples of the solution and examined slices of them to determine the effects of various parameters on particle size.

The nano-C60 particles that formed were 20 to 500 nanometers across and retained the same properties as C60 molecules – a determination researchers made using nuclear magnetic resonance imaging. This finding is significant because pure C60 is recoverable, therefore enhancing the promise of sustainable fullerene production practices, Fortner noted. Also, electron and powder diffraction techniques revealed that nano-C60 has a particular crystalline structure. These findings reinforced previous research done elsewhere.

"Our work builds on previous findings in an environmental engineering context," Fortner explained. "We wanted to know about nano-C60 formation under a variety of ambient natural conditions."

Researchers found that changing the pH of the water with which C60 is mixed affected particle size. A higher pH, such as 9, yielded smaller particles, and a lower pH, such as 5, yielded larger particles. Also, the rate at which C60 is mixed with water affected particle size. A slower rate resulted in larger particles, and a faster rate produced smaller ones.

"This research is the first to show control over the particle formation processes based on these parameters," Fortner said. Researchers also examined the stability of these particles as a function of ion concentration in the water. Because nano-C60 particles rely on a negatively charged surface to remain suspended in water, the presence of elevated concentrations of ions, such as dissolved NaCl (table salt), can render the surface neutral. If that happens, nano-C60 particles sink to the bottom of the solution container and form a solid glob, Fortner explained.

"In the laboratory, scientists typically use de-ionized water, but that’s not the case in nature," Fortner said. "At some level, salt is present, even in groundwater. We found that even in water with the normal salt concentration of groundwater, nano-C60 particles still remain suspended for months. However, in simulated sea water, the particles are neutralized and sink in a matter of hours." Researchers don’t yet know the full implications of this finding, Fortner added.

"We’ve just developed a conceptual model so far, and it doesn’t take into account all of the unknowns or heterogeneity found in the environment," Fortner said. "We studied the most controlled situations and got preliminary data."

Jane M. Sanders | EurekAlert!
Further information:
http://www.edi.gatech.edu

More articles from Materials Sciences:

nachricht Beyond conventional solution-process for 2-D heterostructure
22.06.2018 | Science China Press

nachricht Graphene assembled film shows higher thermal conductivity than graphite film
22.06.2018 | Chalmers University of Technology

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>