Can the world burn fossil fuels for energy in a way that doesn’t contribute to global warming? What can be done to protect people from the release of toxic chemicals? How would NASA care for a sick astronaut during long-duration space explorations like a manned mission to Mars?
These are some of the problems that drive M. Douglas LeVan, J. Lawrence Wilson Professor of Engineering and professor of chemical and biomolecular engineering at the Vanderbilt University School of Engineering.
A leader in the field of adsorption, LeVan seeks to improve air quality both on Earth and in space. Working at the interface between pure research and its applications, he and his team of researchers are developing new materials and striving to understand old ones better.
Adsorption involves the use of solids to filter substances from either gases or liquids. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid.
“My research has focused almost entirely on gas phase adsorption onto different materials,” he says. The results have implications for the environment, space exploration and the military.
New Developments for Greenhouse Gases
Currently, his research group studies adsorption of gases on nanoporous materials. Such materials contain pores smaller than a nanometer (one billionth of a meter). In addition to applying theory, the team uses models and experiments in air separation, gas storage, the removal of trace contaminants and other applications.
For example, the researchers are working on developing new metal organic framework adsorbents to remove carbon dioxide from the flue gases of coal-fired power plants. Funded by the U.S. Department of Energy, this research may help reduce the greenhouse gases that contribute to climate change.
“The object is to capture carbon dioxide and concentrate it enough to store in old wells or use it to drive oil and natural gas to producing wells for enhanced recovery,” he explains.
LeVan has received continuous research support from the U.S. Army for more than 20 years. Currently, his group is working with the Army to develop new adsorbent materials and to study equilibrium and rate properties of new and existing adsorbents.
Into Space and Back
During the past 15 years, LeVan’s NASA research has involved many aspects of advanced life support and in situ resource utilization. Current collaborations include the development of small medical oxygen concentrators that will help keep astronauts healthy during long-duration space missions.
“Our goal is to take air from the spaceship cabin and enrich part of it in oxygen for astronauts who might become ill during the mission,” LeVan says.
Another project involves compressing oxygen to very high pressures using adsorption technology. The oxygen could then be used by astronauts on extravehicular activity expeditions from the International Space Station and on future manned missions to Mars, where resupply is impossible. The pressurized oxygen could also be used in propulsion to burn fuel.
LeVan is also investigating the improvement of systems for the removal of trace contaminants and carbon dioxide from spacecraft cabins. This research could help prevent situations like that experienced by the Apollo 13 crew in 1970 (and depicted in the movie Apollo 13), in which CO2 levels became too high in the space capsule, threatening the astronauts’ lives. LeVan says that by using adsorption and hydrogen, the CO2 could produce water and methane. The water, in turn, could be converted into oxygen for breathing and hydrogen for fuel.
Teaching and Research
Formerly a member of the engineering faculty at the University of Virginia, LeVan came to Vanderbilt as Centennial Professor and chair of the Department of Chemical Engineering in 1997. He has been a Fulbright Scholar to Portugal and France and a visiting professor at Perpignan University in France and the University of Queensland in Australia. Considered one of the top experts on adsorption processes, he also has edited and authored numerous books and articles and consulted with international clients, including fuel cell innovator Bloom Energy. In 2008, he stepped down from department chair to devote more time to teaching and research.
It is in those arenas that LeVan prefers to be. When he speaks of research, the world-renowned leader in chemical engineering sounds like an artist, using phrases like “beautiful structures” and “exquisite frameworks.” When he speaks of teaching, he admits, “I’d much rather work with students on these types of projects for the joy of it.”