New material traps radioactive waste like a Venus flytrap
Chemical material could speed clean-up at power plants by snapping its jaws at radioactive waste, leaving nontoxic byproducts alone.
Mon, Mar 01 2010 at 9:17 PM
Venus flytraps are notoriously picky eaters. Drop a pebble into their open jaws and they won't bite, but they instinctively know to snap shut when a fly enters. Now scientists have invented a chemical material that acts in a similar fashion. Unlike the carnivorous plant, the material's favorite food is radioactive waste.
PhysOrg.com reports that the newly discovered material has the potential to speed up the cleaning of power plants and contaminated sites, potentially making nuclear energy a safer option for the environment. Before the invention of this material, sorting out deadly isotopes from harmless ions in waste was an arduous and inefficient process.
"The name of the game in cleaning up nuclear waste is to concentrate the dangerous isotopes as efficiently as possible," said Mercouri Kanatzidis, one of the scientists who crafted the new technology. "That's where this new material does its job."
Nuclear waste from power plants contains nontoxic sodium ions and radioactive cesium isotopes. The radioactive cesium is dangerous, especially if it leaches into soil and the water supply, because its half-life is around 30 years. That means it can remain in the environment for decades. In fact, cesium-137 contamination is one of the main reasons the Ukrainian town of Chernobyl is still considered unsafe 25 years after the nuclear accident that made the name infamous.
The new material works because its crystalline structure is specially designed to bond in a different way with cesium than with sodium, trapping the former but releasing the latter. Since cesium ions don't bond as well as sodium ions bond with water molecules, only the sodium ions manage to pull through the material when it is dipped in a solution to prompt ion exchange. Cesium, on the other hand, binds to sulfur atoms embedded in the rings of the material's framework, causing a hole to seal shut around it.
"As far as we know, this Venus-flytrap process is unique," Kanatzidis said. "It also works over a large range of acidities — an essential property for clean-up at different sites around the world, where pH can range considerably."
The discovery of Venus flytrap-like materials may sound like something out of a comic book (or the theme of a sequel to Little Shop of Horrors), but this is one eco-invention that could be worth another look, especially if President Obama continues his current push to increase the U.S. supply of nuclear power.
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