In the Lab

• By Jim DiPeso
• Mar 01, 2001

Closer to the atmosphere

The Johns Hopkins University and NASA's Goddard Space Flight Center are planning to make a new instrument for tracking changes in the earth's ozone layer. They envision a powerful fiber-optic laser system that could communicate critical information about the health of the atmosphere -- perhaps even the truth about global warming.

This laser device promises to become the critical component of a LIDAR system, a variation of radar that uses light instead of radio waves. The tool would be mounted inside a satellite high above the Earth, firing ultraviolet beams toward the planet, taking notes on the gas molecules touched in the Earth's atmosphere. The information gathered bounces back to the satellite in the beam, carrying a wavelength absorption "fingerprint" containing information about the identity of gases in the atmosphere and their density. The system could be used to measure changes in the protective ozone layer that surrounds the Earth.

Within five to seven years, this cutting-edge tool could be in orbit, gathering important data for scientists who monitor air pollution and atmospheric changes that may be associated with global warming.

NASA awarded an $815,500 three-year grant to the team that plans to design and build a prototype of this device. Jin Kang, an assistant professor in Johns Hopkins' Department of Electrical and Computer Engineering, will create the ultraviolet light source based on fiber-optic laser technology. Engineers at Goddard will fabricate a sturdy housing that will protect the system from the rigors of space travel.

The engineers from Johns Hopkins and Goddard hope to finish building their fiber-optic laser device within three years. Afterward, the same team hopes to incorporate the laser into a larger research instrument that could be launched into space a few years later.

"This kind of laser is ideal for space applications, where it has to be able to survive the rocket vibrations and remain operating in space for a long time," Kang says. "In a fiber-optic laser, the light keeps going around a loop of fibers and gets amplified as it does. It's very simple, and you don't have to align mirrors the way you do with a conventional laser. A fiber-optic laser is very light and highly efficient."

"We're going to integrate Kang's basic laser into our equipment, making the parts rugged enough to survive space travel and miniaturizing some parts to reduce the size and weight," said Harry Shaw, associate branch head for component technology and radiation effects at Goddard. "We're going to develop a device that is compact, reliable and weighs much less than conventional lasers. That's very attractive to spacecraft designers."

For more information visit John Hopkins University at www.jhu.edu.

Medicine made well

Roche Colorado Corporation (RCC) was recently honored with a Presidential Green Chemistry Challenge Award for their innovative chemistry to protect the environment.

RCC manufactures Cytovene7 -- used in the treatment of cytomegalovirus retinitis infections in immunocompromised patients, including those with Acquired Immune Deficiency Syndrome (AIDS) and recipients of solid tissue transplants.

President Clinton established the Presidential Green Chemistry Challenge, in 1995, to promote the design of chemical products and manufacturing processes that prevent pollution and are economically competitive. Since 1996, these awards have been presented annually at the National Academy of Sciences in Washington, D.C.

RCC developed the first commercial process for Cytovene7 in the early 1990s. By 1993, RCC's Boulder Technology Center designed an expedient new process for the production of the drug, which at the time had an estimated demand of approximately 50 metric tons per year. Significant environmental improvements were found in the second generation Guanine Triester process(GTE).

Improvements to the GTE process reduced the number of chemical reagents and intermediates from 22 to 11, eliminated the only two hazardous solid waste streams, eliminated 11 different chemicals from the hazardous liquid waste streams and, of the five ingredients not incorporated into the final product, 4 of the ingredients were efficiently recycled and reused. Additionally, the product yield was increased by 25 percent.

Specifically an alkylation step utilizing benzyl chloride -- a highly toxic and cancer suspect agent -- was eliminated. The process step using p-toluenesulfonic acid, a corrosive and toxic reagent was removed, and pyridine, a flammable and toxic liquid, was eliminated along with others.

RCC has met a basic principle of the Presidential Green Chemistry Challenge Program -- the development of environmentally friendly processes for the manufacture of pharmaceutical products.

The GTE is registered with the FDA as the current manufacturing process for the world's supply of Cytovene7 and is generally applicable to the synthesis of other antiviral agents, such as acyclovir (Zorivax7).

For more information visit the American Chemical Society at www.acs.org.

NO_x under control

Researchers at Argonne National Laboratory have developed a new software technology that allows utilities to improve control of nitrogen oxides (NO_x) emissions.

The software is designed to work with the Gas Research Institute's fuel lean gas reburn technology, a process that injects controlled amounts of natural gas into the upper furnaces of coal-fueled boilers. The natural gas reburns the NO_x gases, converting them to elemental nitrogen, which makes up approximately 80 percent of the earth's natural atmosphere.

Argonne engineers, working with industrial partner Energy Systems Associates (ESA), developed a controller that advises power plant operators when NO_x emissions are too high and suggests the appropriate degree of lean gas reburn adjustments to reduce them.

The intelligent controller learns the power plant behavior using artificial intelligence methods, such as neural networks and fuzzy logic. Neural networks learn like a human does, by trial and error. The controller learned to mimic the complex plant processes in the boiler by analyzing performance data collected from a ComEd power plant.

"Since natural gas is more expensive than coal," said Jaques Reifman, the Argonne project leader, "we're interested in developing a control system that will help plant operators use natural gas economically while maintaining the required NO_x reductions."

With the controller, utilities can easily balance the price of gas against the expense of buying emissions allowances-which cost about $2,000 or more per ton of NO_x during the ozone season.

"Initial simulation tests on coal-fueled boilers showed that the new controller consistently leads to greater NO_x reduction and lower average rates of natural gas consumption when compared with manual control. The plant performance database includes the amount and distribution of natural gas and the resulting NO_x levels," Reifman said.

When installed in a coal-fired power plant, the NO_x controller is projected by Reifman to pay for itself within one year. Reducing pollution, however, is priceless.

For more information,visit www.anl.gov.

Cyanide fears extinguished

Hydrologists with the U.S. Department of Energy's (DOE) Los Alamos National Laboratory determined that the vast majority of cyanide found in storm water after the Cerro Grande fire was not in a form that could injure humans, fish or other living organisms. In addition, the hydrologists have found that some of the cyanide may have been naturally created by combustion.

In September, laboratory hydrologists at the Los Alamos National Laboratory reported the presence of cyanide in storm water that was running onto Laboratory property. The hydrologists believed that a possible source for the chemical was sodium hexacyanoferrate (II) -- also known as sodium ferrocyanide -- used in slurry, an air-dropped fire retardant. Sodium ferrocyanide is added to slurry as an anti-caking agent and corrosion inhibitor.

U.S. Forest Service data show that approximately 167,000 gallons of slurry containing sodium ferrocyanide were dropped while fighting the Cerro Grande fire.

When analyzing samples for cyanide, technicians look for amenable cyanide, a form that kills fish or poisons living things, and bound cyanide, a form of the chemical that is less harmful and more stable -- provided that bound cyanide does not undergo changes induced by ultraviolet light and water, or other factors. Sodium ferrocyanide can degrade into amenable cyanide in the presence of ultraviolet light, such as sunlight, and in water.

After reviewing research regarding forest-fire-created contaminants, the hydrologists found scientific papers that indicate quantities of cyanide can be produced naturally by a smoldering fire, as well. These cyanide-containing compounds may remain in ash.

Laboratory and New Mexico Environment Department (NMED) results from the analysis of ash samples from areas burned by the Cerro Grande fire, but untouched by slurry fire retardant, show cyanide in concentrations of several parts per million. Accordingly, cyanide can come from naturally occurring sources, as well as, possibly from the slurry.

In addition, the majority of the cyanide found in runoff samples to date is in a form that is not harmful to fish, animals or people.

Scientists with the U.S. Environmental Protection Agency (EPA) subjected a species of minnow and a species of insect to acute and chronic exposures of the storm water. The water had no deleterious effect on the test subjects in acute-exposure tests. However, in some of the chronic-exposure tests, the insect species died -- scientists are unsure whether the cyanide or other factors were responsible.

The key question remaining to researchers is what happens to cyanide after it is exposed to alternating cycles of sunlight and rainfall.

Los Alamos researchers are collaborating with researchers from EPA, NMED and the U.S. Forest Service to compare samples collected here with samples collected at other nearby fire-damaged areas. Scientists will also use areas within the Cerro Grande fire burn zone as a natural study site to look at cyanide and other fire-chemistry issues. Los Alamos hydrologists will continue to test for and report on cyanide and other substances of concern in runoff.

"The really good part of this story is that we have new information that shows the potential hazards posed by short-term exposure to the cyanide are reduced," said Bruce Gallaher of the Laboratory's Water Quality and Hydrology Group. "Most test results show levels that are not known to pose a hazard to fish or wildlife. In fact, we have no reports of fish kills or impacts to the Rio Grande as a result of the Cerro Grande fire."

For more information, visit www.anl.gov.

This article originally appeared in the March 2001 issue of Environmental Protection, Vol. 12, No. 3, p. 14.

This article originally appeared in the 03/01/2001 issue of Environmental Protection.