SCIENCE INDEX 2000 2001 2002 Materials

University lands research center for advanced water purification

Jim Kloeppel, Physical Sciences Editor
(217) 244-1073; kloeppel@uiuc.edu

9/19/02

CHAMPAIGN, Ill. -- The University of Illinois at Urbana-Champaign has received a grant from the National Science Foundation to create a science and technology center to develop advanced materials and technologies for water purification. The grant will provide $4 million in funding for each of five years, with the possibility of a five-year renewal.

"The world is heading toward a severe water crisis," said James Economy, a professor of materials science and engineering at Illinois and the director of the new center. "There are intelligence reports saying that within a decade or two, water -- not food or fuel -- will be the most serious shortage the world faces."

According to the United Nations, an estimated 1 billion people do not have access to clean, fresh water. Each year, 5 million people die of waterborne illnesses. The world's growing population will exacerbate the problem.

"The goal of the center is to develop revolutionary materials and systems for safely and economically purifying water to counter the impending crisis," Economy said. "Research will focus on improving disinfection and desalination processes, removing trace contaminants, and eliminating foulants that clog filters and reduce their effectiveness."

Illinois is the lead university for the center. Partner institutions are Clark Atlanta University and Stanford University; affiliated institutions are Ohio State University and the University of California at Berkeley.

At Illinois, scientists and engineers from the departments of chemical engineering; chemistry; civil and environmental engineering; geology; materials science and engineering; and mechanical and industrial engineering will be involved with the center, as well as researchers from the Waste Management and Research Center on campus.

Some of the center's work will build upon carbon-fiber technology developed at Illinois. This improved adsorption process begins with inexpensive glass fibers, which can be woven into wear-resistant fabrics. The glass fabrics are dipped in a phenolic resin and then "activated" through a chemical reaction that etches small pores into the carbon. The nature of the reaction determines both the pore structure and pore-surface chemistry, which control the adsorption properties of the coated assemblies.

"Our ability to tailor the pore size and surface chemistry of the fibers provides us with a unique capability to design highly selective systems for enhanced adsorption of specific contaminants, such as pesticides and chlorinated hydrocarbons," Economy said. "Another family of ion exchange fibers has been developed that is extremely effective at removing trace metallic contaminants, such as lead, arsenic and mercury."

New membranes developed at the center will have micropores resembling those in the carbon fibers, Economy said. Extending through the membranes, these microchannels could offer a low-cost alternative to the reverse osmosis process currently used for desalination. Researchers will examine ways to tailor the surface chemistry of the membranes for specific adsorption properties and to enhance the hydrophilic character of the micropores.

Scientists at the center also will explore a new concept based upon phase-change materials. In one variation, researchers will examine the rapid crystallization and dissolution of water as a means of desalination, while in another they will look at the use of gas hydrates as a source of potable water.

Found on the ocean floor, these crystalline materials -- called clathrates -- form when water molecules create a cage-like structure around "guest molecules" such as methane, propane or isobutane. As clathrates form, the ocean's salt separates out, offering a potential supply of fresh water. Scientists will investigate techniques to efficiently split these materials into clean drinking water and fuel.