Featured Research

from universities, journals, and other organizations

Brookhaven Scientists Reveal How Catalysts Adsorb Pollutants

Date:
March 28, 2000
Source:
Brookhaven National Laboratory
Summary:
Better catalytic converters and smokestack "scrubbers" could help keep pollutants out of the air. Studies on how pollutants stick to or are broken apart by certain materials, now under way at the U.S. Department of Energy's Brookhaven National Laboratory, could be a step in that direction.

Findings may help engineers build a better pollution trap

UPTON, NY - Better catalytic converters and smokestack "scrubbers" could help keep pollutants out of the air. Studies on how pollutants stick to or are broken apart by certain materials, now under way at the U.S. Department of Energy's Brookhaven National Laboratory, could be a step in that direction. Brookhaven scientists will present results of one aspect of this work - how magnesium oxide (MgO) adsorbs hydrogen sulfide (H2S) - at a March 23 session of the American Physical Society meeting in Minneapolis.

Sulfur is a common impurity in fossil fuels. Upon combustion, sulfur byproducts such as H2S can contribute to air pollution and acid rain. To keep these pollutants out of the atmosphere, catalytic converters and smokestack scrubbers typically contain metal-oxide catalysts that adsorb the pollutants - that is, cause them to stick to the catalyst surface.

"But many of these devices were designed on a trial-and-error basis, without understanding the detail of how they actually work," says Brookhaven chemistry department research associate Andrea Freitag. Furthermore, the catalysts typically used are made from expensive metals like platinum and rhodium. Over time, some of these catalysts lose their ability to adsorb pollutants, "like a Slinky that loses its springiness due to overuse," says John Larese, a senior scientist in Brookhaven's chemistry department.

Freitag and Larese are working to develop new catalysts based on less-expensive metals like magnesium and zinc, and are conducting molecular-level studies of how the pollutants and catalysts interact. Their findings may help engineers build a better pollution trap.

For example, the scientists have used X-ray diffraction techniques at Brookhaven's National Synchrotron Light Source and neutron scattering at facilities in Europe to take molecular level "pictures" of how the pollutant molecules adhere to the catalyst crystals. In accompanying thermodynamic studies, in which the catalyst is held at a constant temperature while the pressure of a pollutant gas above it increases, the scientists calculate the capacity of the catalyst to adsorb the pollutant.

"These studies enable us to match what's happening thermodynamically with what's happening microscopically," Larese says. For example, the team has shown that when H2S adsorbs on MgO, two or three uniform layers form at distinct intervals as the pressure increases.

The studies also show that the adsorption process can be reversed if the catalyst is heated to release the adsorbed gases. That means the catalyst can be used over and over, eliminating the "worn-out Slinky" problem.

The Brookhaven scientists are also looking at ways to tailor-make MgO and other catalyst crystals to increase their adsorbing capacity, for example, by altering the crystals' size or shape to increase their surface area, or by doping the crystals' surfaces with other reactive metals such as zinc, nickel, chromium and copper.

The structural and thermodynamic studies are the key, Larese says; "You can make a better catalyst if you understand the process."

This paper will be presented at session V15 on March 23, 2000, at 2:30 p.m. in room 205B of the Minneapolis Convention Center.

The U.S. Department of Energy's Brookhaven National Laboratory creates and operates major facilities available to university, industrial and government personnel for basic and applied research in the physical, biomedical and environmental sciences and in selected energy technologies. The Laboratory is operated by Brookhaven Science Associates, a not-for-profit research management company, under contract with the U.S. Department of Energy.


Story Source:

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


Cite This Page:

Brookhaven National Laboratory. "Brookhaven Scientists Reveal How Catalysts Adsorb Pollutants." ScienceDaily. ScienceDaily, 28 March 2000. <www.sciencedaily.com/releases/2000/03/000327084813.htm>.
Brookhaven National Laboratory. (2000, March 28). Brookhaven Scientists Reveal How Catalysts Adsorb Pollutants. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2000/03/000327084813.htm
Brookhaven National Laboratory. "Brookhaven Scientists Reveal How Catalysts Adsorb Pollutants." ScienceDaily. www.sciencedaily.com/releases/2000/03/000327084813.htm (accessed July 23, 2014).

Share This




More Earth & Climate News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Orleans Plans to Recycle Cigarette Butts

New Orleans Plans to Recycle Cigarette Butts

AP (July 21, 2014) New Orleans is the first U.S. city to participate in a large-scale recycling effort for cigarette butts. The city is rolling out dozens of containers for smokers to use when they discard their butts. (July 21) Video provided by AP
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
Spectacular Lightning Storm Hits London

Spectacular Lightning Storm Hits London

AFP (July 19, 2014) A spectaCular lightning storm struck the UK overnight Friday. Images of lightning strikes over the Shard and Tower Bridge in central London. Duration: 00:23 Video provided by AFP
Powered by NewsLook.com
A Centuries' Old British Tradition Is Far from a Swan Song

A Centuries' Old British Tradition Is Far from a Swan Song

AFP (July 19, 2014) As if it weren't enough that the Queen is the Sovereign of the UK and 15 other Commonwealth realms, she is also the owner of all Britain's unmarked swans. Duration: 02:18 Video provided by AFP
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