Featured Research

from universities, journals, and other organizations

Tiny Particles Could Solve Billion-dollar Problem

Date:
March 8, 2005
Source:
Rice University
Summary:
New research from Rice University's Center for Biological and Environmental Nanotechnology finds that nanoparticles of gold and palladium are the most effective catalysts yet identified for remediation of one of the nation's most pervasive and troublesome groundwater pollutants, trichloroethene or TCE.

HOUSTON, Feb. 23, 2005 -- New research from Rice University's Center for Biological and Environmental Nanotechnology finds that nanoparticles of gold and palladium are the most effective catalysts yet identified for remediation of one of the nation's most pervasive and troublesome groundwater pollutants, trichloroethene or TCE.

The research, conducted by engineers at Rice and the Georgia Institute of Technology, will appear next month in the journal Environmental Science and Technology, a publication of the American Chemical Society.

"The advantages of palladium-based TCE remediation are well-documented, but so is the cost," said lead researcher Michael Wong, assistant professor of chemical engineering and chemistry at Rice. "Using nanotechnology, we were able to maximize the number of palladium atoms that come in contact with TCE molecules and improve efficiency by several orders of magnitude over bulk palladium catalysts."

TCE, which is commonly used as a solvent to degrease metals and electronic parts, is one of the most common and poisonous organic pollutants in U.S. groundwater. It is found at 60 percent of the contaminated waste sites on the Superfund National Priorities List, and it is considered one of the most hazardous chemicals at these sites because of its prevalence and its toxicity. Human exposure to TCE has been linked to liver damage, impaired pregnancies and cancer.

Cleanup costs for TCE nationwide are estimated in the billions of dollars. The Department of Defense alone estimates the cost of bringing its 1,400 TCE-contaminated sites into EPA compliance at more than $5 billion.

The typical approach to getting rid of TCE involves pumping polluted groundwater to the surface, where it can be exposed to chemical catalysts or microorganisms that break the TCE down into less toxic or non-toxic constituents. In general, chemical catalysis offers faster reactions times than bioremediation schemes but also tends to be more expensive.

One of the major advantages of using palladium catalysts to break down TCE is that palladium converts TCE directly into non-toxic ethane. By contrast, breaking down TCE with more common catalysts, like iron, produces intermediate chemicals, like vinyl chloride, that are more toxic than TCE.

In the CBEN experiments, Wong and collaborators compared the effectiveness of four varieties of palladium catalysts: bulk palladium, palladium powder on an aluminum oxide support base, pure palladium nanoparticles and a hybrid nanoparticle developed by Wong that consists of a gold nanoparticle covered with a thin coat of palladium atoms.

As metal particles get progressively smaller, a higher percentage of the atoms in the particle are found on the surface of the particle instead of being locked away inside the metal where they cannot interact with other chemicals. For example, in the bulk palladium, less than 4 percent of the palladium atoms were on surface of the particle. Pure palladium nanoparticles had 24 percent of the metal on the surface. In the gold-palladium nanoparticles, 100 percent of the palladium atoms are accessible for reaction.

"We've documented the efficiency of these catalysts in breaking down TCE, and the next step is engineering a system that will allow us to get at the polluted groundwater," said Joe Hughes, professor of civil and environmental engineering at Georgia Institute of Technology and a co-leader of CBEN's environmental research programs. "The scale of TCE contamination is enormous, so any new scheme for TCE remediation has got to clean large volumes of water very quickly for a just a few pennies."

Hughes, Wong and their collaborators hope to develop a device that would include a cylindrical pump containing a catalytic membrane of the gold-palladium nanoparticles. The device would be placed down existing wells where it would pump water through continuously, breaking TCE into non-toxic components.

Cost is the primary hurdle to cleaning up TCE-polluted groundwater. CBEN's team hopes to drive down costs by using every ounce of palladium to maximum efficiency, and by eliminating drilling costs for new wells, construction costs for surface treatment facilities and energy costs of lifting water to the surface.

Nanotechnology is critical to the scheme because only a nanoscale catalyst will be efficient enough to provide the throughput needed to make the whole approach effective. Tests in Wong's lab have found that the gold-palladium nano-catalysts break TCE down about 100 times faster than bulk palladium catalysts.

CBEN's research is funded by the National Science Foundation.


Story Source:

The above story is based on materials provided by Rice University. Note: Materials may be edited for content and length.


Cite This Page:

Rice University. "Tiny Particles Could Solve Billion-dollar Problem." ScienceDaily. ScienceDaily, 8 March 2005. <www.sciencedaily.com/releases/2005/02/050224121521.htm>.
Rice University. (2005, March 8). Tiny Particles Could Solve Billion-dollar Problem. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2005/02/050224121521.htm
Rice University. "Tiny Particles Could Solve Billion-dollar Problem." ScienceDaily. www.sciencedaily.com/releases/2005/02/050224121521.htm (accessed July 23, 2014).

Share This




More Matter & Energy News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Government Approves East Coast Oil Exploration

Government Approves East Coast Oil Exploration

AP (July 18, 2014) The Obama administration approved the use of sonic cannons to discover deposits under the ocean floor by shooting sound waves 100 times louder than a jet engine through waters shared by endangered whales and turtles. (July 18) Video provided by AP
Powered by NewsLook.com
Sunken German U-Boat Clearly Visible For First Time

Sunken German U-Boat Clearly Visible For First Time

Newsy (July 18, 2014) The wreckage of the German submarine U-166 has become clearly visible for the first time since it was discovered in 2001. Video provided by Newsy
Powered by NewsLook.com
Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Reuters - US Online Video (July 17, 2014) President Barak Obama stopped by at a lunch counter in Delaware before making remarks about boosting the nation's infrastructure. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

TheStreet (July 16, 2014) Oil Futures are bouncing back after tumbling below $100 a barrel for the first time since May yesterday. Jeff Grossman is the president of BRG Brokerage and trades at the NYMEX. Grossman tells TheStreet the Middle East is always a concern for oil traders. Oil prices were pushed down in recent weeks on Libya increasing its production. Supply disruptions in Iraq fading also contributed to prices falling. News from China's economic front showing a growth for the second quarter also calmed fears on its slowdown. Jeff Grossman talks to TheStreet's Susannah Lee on this and more on the Energy Department's Energy Information Administration (EIA) report. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins