In the Lab

• Sep 01, 2003

Alternative Fuel: Platinum is Out, Plants Are In
Scientists have developed a hydrogen-making catalyst that uses cheaper materials and yields fewer contaminants than do current processes, while extracting the element from common renewable plant sources. An article published in the June 27 issue of the journal Science states the new catalyst lies at the heart of a chemical process that is a significant advance in producing alternate fuels from domestic sources.

After testing more than 300 metal combinations, James Dumesic, John Shabaker and George Huber, of the University of Wisconsin at Madison, report developing the catalyst from nickel, tin and aluminum and using it in a process called aqueous-phase reforming (APR), which converts plant byproducts to hydrogen. The process reportedly performs as well as current methods that use precious metals such as platinum, yet runs at lower temperatures and is much cleaner.

"The APR process can be used on the small scale to produce fuel for portable devices, such as cars, batteries and military equipment," said Dumesic. "But it could also be scaled up as a hydrogen source for industrial applications, such as the production of fertilizers or the removal of sulfur from petroleum products."

Hydrogen is a "clean" fuel because when it burns, it combines with oxygen to form water without producing toxic byproducts or greenhouse gases in the process. The APR process extracts hydrogen from a variety of biological sources, especially simple carbohydrates and sugars generated by common plants.

The precious metal platinum is well known to be an excellent catalyst in a number of chemical reactions. Yet, platinum is rare and very expensive, costing more than $17 per gram (about $8,000 per pound).

According to Dumesic, a substitute for platinum catalysts is essential for the success of hydrogen technology. "We had to find a substitute for platinum in our APR process for production of hydrogen, since platinum is rare and also employed in the anode and cathode materials of hydrogen fueld cells to be used in products such as cars or portable computers," he said.

The team is now collaborating with scientists at Virent Energy Systems in Wisconsin as part of a National Science Foundation (NSF) Small Business Technology Transfer (STTR) grant to develop catalysts for generating fuels from biomass. An independent federal agency that supports research and education in science and engineering, NSF's small business program aims to increase the incentive and opportunity for small firms to undertake cutting-edge, high-risk and high-quality research that has a high potential economic payoff.

The U.S. Department of Energy and the Materials Research Science and Engineering Center on Nanostructured Materials and Interfaces at the University of Wisconsin provided additional support for this research.

Excuse You! Cow Breath, Burps Blamed for Greenhouse Gas
Even on mornings when the world's strongest breath mint can't help your bad breath, you can still be thankful that you're not a cow -- with breath that allegedly harms Earth's ozone layer and contributes to global warming.

The collective breathing of cows accounts for nearly 20 percent of the methane gas released into the atmosphere, with a typical cow releasing 100 gallons to 150 gallons of the gas each day. To cut down on this amount, University of Nebraska researchers are working to develop an additive for cattle feed.

"The reason we're focusing on methane is because it's a short-lived, highly potent greenhouse gas that needs to be reduced," said Stephen Ragsdale, biochemistry professor.

The methane produced in a cow's rumen -- the first of a cow's four stomachs -- gets into the bloodstream and exits through the lungs, said Ken Olson, a range livestock nutritionist at Utah State University. Olson said nearly all of the methane comes from breathing, with a tiny bit escaping when a cow belches. Olson conducted a six-year study that found better range management practices, like providing higher quality forage, could make a small difference in the amount of methane released by cattle.

In Nebraska, Ragsdale and fellow researchers James Takacs and Jess Miner have been working for over three years to reduce methane by blocking enzymes in the cow's rumen that are necessary to produce it. The methane-blocking compound would be delivered in an additive to cattle feed, a process the researchers have patented. They are now working with a commercial partner to develop a viable formula.

In the last 18 months, the researchers have tested over 200 compounds, trying to find the right formula that blocks the methane but doesn't harm the beneficial microbes in the cow's rumen. From those, only 10 have been successful enough to be tested on rumen fluid extracted from a steer. "Of those, about 20 to 30 percent are indeed doing what we expect them to do," said Ragsdale. "We're honing in on what would be perfect."

Researchers have not yet tested any compounds in live animals, and Ragsdale would not speculate on when that would happen. Initial testing will likely be in an animal much smaller than a cow. "We'd probably go to sheep before cattle, and before sheep we may go to a termite," he said. "They make a lot of methane."

Human activities, including cultivating livestock, have in the last 200 years altered the chemical composition of the atmosphere through the buildup of greenhouse gases, primarily carbon dioxide, methane and nitrous oxide. These gases are widely seen as contributing most to global climate change, trapping some of the outgoing energy from the Earth and causing heat retention like the glass panels of a greenhouse. The Earth's surface temperature has risen 1 degree in the last 100 years, according to Gregory Symmes with the National Academy of Sciences.

While the Nebraska researchers know they won't eliminate all of the methane emissions from cattle, they are hoping to reduce them by about four percent, which would help restore some equilibrium to the planet's natural method of getting rid of methane from its atmosphere.

With methane's lifetime of 10 years to 12 years in the atmosphere, focusing on reducing this gas would provide quicker benefits to reducing greenhouse gases compared to carbon dioxide's lifetime of 50 years to 200 years.

Long-Lost Algebra May Aid in Resource Management
With the aid of a chance discovery by a graduate student, scientists from Oregon State University (OSU) have found a new use for an old math theory from the early 1800s that could revolutionize the management of lands, protection of species and study of ecology.

The findings, published in the journal American Naturalist, promise to address the enormous complexities of the natural world with the powerful tools of advanced mathematics--which, until now, have been of limited use in the study of many natural resource issues. Existing mathematical approaches have often been relegated to the sidelines, in favor of time-consuming and costly experiments or trial-and-error management.

"This research should have major implications for the management of natural resources around the world," said Philippe Rossignol, a professor of fisheries and wildlife at OSU and co-author of the study. "We're going to be able to apply mathematics to predict what might happen with a great deal more certainty than ever before. It could significantly improve the ability of ecologists, land managers and other scientists to address many issues, anything from the clarity of Crater Lake to fisheries management or emerging diseases."

This new insight began when Rossignol, Jeffery Dambacher, Hans Luh, Hiram Li and other OSU researchers were struggling to resolve a mathematical paradox first suggested in 1973 by a Robert May, a famous ecologist. May's mathematical theory made perfect sense but seemed at odds with the way the world really worked.

"One of the basic concepts of ecology for generations had been that the complexity of the natural world is a big part of what makes it persistent, that the many interrelationships, interactions and food webs among different species evolved into stable systems that worked well together," said Hiram Li, an OSU professor of fisheries and wildlife and co-author of the study. "But Robert May came along with a mathematical theory that suggested that increased complexity in a natural system should actually make it less stable. The math seemed to work perfectly, but our observations of the real world ran contrary to this."

The researchers were struggling with their approach when Dambacher, then an OSU graduate student, had a chance conversation about what was needed with members of the university's math department. They mentioned a largely forgotten theorem of matrix algebra developed in the early 1800s by the French mathematician Augustin Cauchy that appeared to be ideal for the problem at hand.

"It became immediately clear that this mathematical approach would take us in the direction we needed," Rossignol said. "It gives us a way to describe complex natural populations in more realistic terms, consider indirect interactions and really provide a much more accurate view of how natural systems will work. We'll be far more accurate with our predictions and can use this approach in the new field of adaptive management, improving our natural resource management approaches as we go."

In one recent usage, an OSU graduate student used this system to study the stability of an Oregon sea urchin fishery and answer questions about the long-term value of reserves. This would have been almost impossible with real-world experiments, but after the computer ran through 12 million mathematical combinations of possible outcomes, the scientists had the answers they sought.

Global Warming Buried At Sea?
Governments and companies around the world are studying ways to pump greenhouse gases--from power stations, oil platforms or steel mills--into deep, porous rocks where they might be trapped for millions of years and curb a rise in temperatures.

The United States signed a charter on June 25 with the European Union's executive Commission and 12 countries, including Russia, China, Japan, Canada and Brazil, to research the technology in a "Carbon Sequestration Leadership Forum."

"The storage potential is enormous," said Tore Torp of the Norwegian oil company Statoil, which has the world's first commercial store of carbon dioxide (CO₂) in sandstone 1,000 meters under the North Sea. "We believe the CO₂ will stay there for many thousands of years. There is no sign of leakage."

But some environmentalists say the idea is costly and like trying to sweep one of the planet's greatest problems under the carpet.

CO₂ is the main gas blamed for blanketing the planet and driving up temperatures, which in turn disrupts the climate with more frequent floods, droughts and storms that could trigger everything from desertification to higher sea levels.

In a U.S. project, drills near a coal-fired power plant run by American Electric Power in West Virginia have reached about 1,200 meters in a search for CO₂ storage sites in sandstone as deep as 3,000 meters below the Ohio River Valley. Under the scheme, CO₂ would be filtered from American Electric's 1,300 mw Mountaineer power plant and buried. CO₂ might be injected into nearby oilfields where it could help raise the amount of oil being pumped out.

Still, many environmentalists see CO₂ storage as a distraction from shifting to clean, renewable energy like wind or solar power and away from dirty fossil fuels like coal and oil. They also say CO₂ storage could prolong dependence on fossil fuels.

This news item originally appeared in the September 2003 issue of Environmental Protection, Vol. 14, No. 7.

This article originally appeared in the 09/01/2003 issue of Environmental Protection.