Spotlight on Research: Krekeler Looks to Nature for Tools to Clean Environment

Posted: July 8, 2005 at 1:00 am, Last Updated: November 30, -0001 at 12:00 am

By Lynn Burke

Two months spent volunteering as an environmental consultant in Honduras led geologist Mark Krekeler, Environmental Science and Policy (ESP), to the realization that there was a need for natural materials that could be used to clean the environment. Krekeler turned his focus to clay mineralogy and the resulting work has yielded two provisional patents and plans for a third patent on technologies that can address this need.

Mark Krekeler
Mark Krekeler
Photo by David Smith

“Clay mineralogy has sort of been the first nanotechnology, which is essentially anything scientists can manipulate at or near the atomic or molecular scale,” says Krekeler. “Clay mineralogists think of clays as nature’s nanoparticles. They do fascinating things. Clays are very useful in their natural state, and when we start modifying them at the nanoscale, wonderful things start to happen.”

The technologies that Krekeler plans to commercialize soon are the result of work he and three of his undergraduate geology students have accomplished since he joined the ESP faculty just over a year ago. The first technology on which a provisional patent has been filed is a counter-weapon containment process that could be employed during a release of radioactive cesium chloride (CsCl). The technology gives military and police forces a low-cost, easy-to-use, effective tool for responding to urban combat incidents.

“Countries in the former Soviet Union have a lot of radiological materials not accounted for, which is very problematic,” says Krekeler. “This is the stuff that terrorists could easily acquire and use as a weapon.” With the help of senior Steve Elmore, Krekeler has developed a clay mineral suspension that can absorb CsCl. Should the radioactive powder be released through a dirty bomb or other mechanism, the suspension could be sprayed on the powder, preventing it from being dispersed further. The resulting slurry could then be collected and heated, transforming the soft, water-soluble CsCl powder into a hard, insoluble material. This process would deweaponize the radioactive material and limit its risks to human health and economic concerns.

The second technology on which a provisional patent application has been filed provides a low-cost method for cleaning many types of polluted groundwater. “With the costs of doing environmental remediation ever increasing, one strategy is to help nature take care of the problem,” he says. One of nature’s tools for cleaning water is bacteria, which decompose the pollutant. With the help of senior Danielle Stoll, Krekeler has taken basic sugars, glucose and sucrose, and exchanged their molecules with montmorillonite, a silicate clay, producing an intercalate gel in which nanolayers of the silicate are stacked with nanolayers of the sugars. After the gel is injected into a groundwater system, the sugar comes off the clay and boosts bacteria levels in the water.

“The technology has a double-whammy effect,” says Krekeler. “Because the clay particles are small, they tuck in between the grains of sand and reduce the flow of water through the groundwater system, greatly slowing the spreading of the pollutant.”

Krekeler has also disclosed a third technology on which another provisional application will be filed soon. This technology concerns an artificial soil that could be used in creating new wetlands that are required as part of state and federal wetland mitigation efforts. According to Krekeler, nearly 90 percent of created wetlands do not work well or even fail, largely because the materials used in created wetlands are not similar to those occurring in their natural counterparts. Senior Cindy Tselepis is assisting with this project.

Krekeler notes that although applied clay mineralogy has been around since the late 1940s, it is only within the past 10 years that better transmission electron microscopy and X-ray diffraction techniques have enabled scientists to really understand the fine details of these materials. “There’s just a wide range of possibilities now with these more sophisticated analytical techniques,” he says. “I think we’ve just scratched the surface as far as developing new technologies with clay materials.”

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