Completing the loop

The saying “what goes around comes around” has a particular resonance for Pratim Biswas, Ph.D., the Stifel and Quinette Jens Professor of Environmental Engineering Science.

Twenty-three years ago, as a master’s degree candidate at the University of California, Los Angeles, Biswas did a thesis on heat transfer, with an eye toward solar power, with one of the applications being solar-powered air conditioning units. At the time, solar power was a hot technology.

Biswas met a young undergraduate chemical engineering student there named Jay R. Turner. After a productive, though hectic, year at UCLA, Biswas went for a doctorate in mechanical engineering at California Institute of Technology.

From there, it went like this: Solar power lost its position in the limelight. Turner came to Washington University to get a doctorate under the direction of Milorad P. Dudukovic, Ph.D., now the Laura and William Jens Professor of Environmental Engineering and chair of the Department of Chemical Engineering.

Turner is now a professor of chemical engineering at the University.

Biswas left CalTech in 1985 for the University of Cincinnati, spending 15 years there and ultimately directing its environmental engineering program. In 2000, he was lured to Washington University to head the Environmental Engineering Science Program, reuniting him with Turner — their office doors are just steps apart.

Turner and Dudukovic are members of the program Biswas directs.

Along with environmental engineering colleagues Richard L. Axelbaum, Ph.D., associate professor of mechanical engineering, and Rudolf B. Husar, Ph.D., professor of mechanical engineering, Biswas helped lure Da-Ren Chen, Ph.D., here — he’s now an assistant professor of mechanical engineering.

And thus, the largest aerosol program in the nation now resides at Washington University.

And, by the way, you might have noticed that solar power is back again.

Leaving Cincinnati was not an easy decision for Biswas and his wife, Sujata.

In 15 years, not only had he established professional roots and helped the program climb in the rankings, but also his family had made many friends and grown comfortable with the community. Their boys, Vivek and Vikran, then 8 and 6, were very reluctant to leave the only home they’d ever known.

“I just kept telling them that they would love St. Louis because it’s similar to Cincinnati,” Biswas said. “My boys didn’t want to root for another baseball team.

“But I pointed out the Rams, who’d just won the Super Bowl, as well as the Cardinals. We’ve all adjusted and love living in St. Louis.”

The boys are active in sports in the Little League and Parkway School District while their father oversees an ambitious program at the University. Biswas is one of a core of six University aerosol researchers within the Environmental Engineering Science Program (which has 10 members, plus three research and affiliated faculty).

These researchers and teachers are mainstream aerosol researchers; they work on different aspects related to aerosol science and engineering.

This internationally recognized group of engineers studies the synthesis and environmental impact of nanoparticles. The scientists also study atmospheric pollution at the regional and global scales.

They are developing the next generation of instrumentation for detection of these particles, as well as several environmental nanotechnology applications.

While the word “aerosol” may imply to a layperson hair sprays or deodorants, in engineering science an aerosol is a gaseous suspension of fine solid or liquid particles. Such particles are often troublesome in the micrometer and nanometer range.

On the plus side, these particles are also finding novel applications in the electronics, pharmaceutical, materials and other industries.

At Cincinnati, Biswas began developing his international reputation by taking a two-pronged approach to aerosol science.

“I saw that in some of these combustion environments, found in cars, diesel engines and coal combustors, you have a process that forms these fine particles; and then by understanding that, we could design effective control strategies and prevent their release in the environment,” he said.

“The other part was to engineer or synthesize materials for specific applications in environmental technology, such as for remediation applications, catalysts to clean up other polluted environments, and so forth. This opened our work to the nanotechnology sector that was just emerging.

“We began synthesizing ceramics and magnetic oxides, all with novel properties, and we were finding newer applications. This is our link to the materials side of aerosols.”

Many aerosols form as a result of combustion, and they have health as well as aesthetic impacts — they get trapped in our lungs and they disturb our views of scenic landscapes. Growing up in India (first in Poona, in western India, and later in Bombay), Biswas developed an early sensitivity to environmental concerns that was honed by his time in southern California.

“I had no idea that I would become an aerosol scientist while at UCLA,” Biswas said. “But solar energy seemed to be waning and I’d always had an interest in energy and the environment, so I chose a Ph.D. project at CalTech that was related to particles being emitted from combustion systems. I designed a device to measure these particles in high-temperature environments.”

Biswas considers his graduate-school years one of the best periods of his life. He learned a lot, met and worked with many influential people, and organized and played for intramural teams in soccer and basketball.

“We worked hard and played hard,” said Biswas, who played basketball as an undergraduate at the world-renowned India Institute of Technology. He chose UCLA for graduate work because it offered a great fellowship as well as a basketball team that he had followed since he was a young boy.

Biswas holds four patents and is author of 110 refereed journal articles. One patent is for a technique that uses nanoparticle agglomerates, or clusters, to firmly bind and remove mercury from fossil fuel combustion exhausts.

Mercury is one of the metals that the U.S. Environmental Protection Agency (EPA) has stipulated must be controlled in combustion systems. Mercury that is released gets deposited in water and finds its way into fish and livestock.

It can remain airborne for more than a year and can be transported over thousands of miles before being deposited to the ground and water. Due to its high toxicity and long residence times in the environment, the EPA is planning to propose regulations for control of emissions of mercury from coal combustion systems.

Another patent is for a device that traps and deactivates microbial particles. The work is promising in the war on terrorism for deactivating airborne bioagents and bioweapons such as the smallpox virus, anthrax and ricin, and also in routine indoor air ventilation applications such as in buildings and aircraft cabins.

Biswas’ device combines an electrical field with soft X-rays and smart catalysts to capture and destroy bioagents.

On the walls of the device, Biswas has coated nanoparticles that catalyze the oxidation. These unique nanoparticles are “smart” objects that are turned “on” and “off” by irradiation.

Biswas and his collaborators have tested the device using non-potent polio virus and have achieved 99.9999 percent efficiency. He is collaborating with the Midwest Regional Center of Excellence for Biodefense and Emerging Infectious Diseases Research (MRCE) and with Largus Angenent, Ph.D., an environmental engineer and assistant professor of chemical engineering, to identify the mechanistic pathways of biomolecular degradation.

Biswas is quick to acknowledge the excellent quality of his graduate students as a factor in his success. He came to the University because of its reputation and the opportunity to build a top-notch aerosols group with critical mass in focused areas of environmental engineering.

“The School of Engineering & Applied Science is extremely grateful to have Pratim Biswas at the helm of our Environmental Engineering Science Program,” said Dean Christopher I. Byrnes, Ph.D., the Edward H. and Florence G. Skinner Professor of Systems Science and Mathematics.

“For the past four years, Pratim has been a passionate researcher and an inspirational leader whose goal for his program is nothing less than to have it become a national and international powerhouse. It is a pleasure for faculty and staff to work with him. He is steadfast, respectful and energetic, and has a delightful sense of humor.”

In just under four years, Biswas has added Angenent, Chen and Daniel Giammar, Ph.D., assistant professor of civil engineering, to the Environmental Engineering Science Program. Biswas proudly notes that the aerosol research group deals with particles “right from the source, from a car engine or flame, to their measurement, their capture, their collection and use for good applications, all the way to tracking them around the globe via satellites.”

“What I think is amazing here at Washington University is that we have a group that completes that loop, from start to finish,” he said. “The field is fascinating and enabling, with applications in health, pharmaceuticals, materials and electronics.

“The ability to make these particles in very controlled sizes, shapes and compositions in a single-step process that lets us study fundamental properties is key, because then companies can make the materials on a mass scale, and the possibilities for materials are virtually endless.”