PSE Success Story:
New Material Traps Radioactive Ions Using “Venus Flytrap” Method
One of the main contaminants
in the Chernobyl disaster zone is
cesium-137, which leaches into
soil and water. With a half-life
of 30 years, it can remain in the
environment, still dangerously
radioactive, for decades.
Nuclear waste from power
plants contains both nontoxic
sodium ions and highly
radioactive cesium isotopes.
Excising the few deadly isotopes
from waste has proved difficult;
most remedial materials don’t
distinguish between the toxic ions
and the harmless ones.
Like a Venus flytrap, a newly discovered chemical material is a picky eater—it won’t snap its jaws shut for just anything. Instead of flies, however, its favorite food is radioactive nuclear waste.
Argonne scientists, in collaboration with Northwestern University, have developed a
sulfide framework that can capture radioactive cesium ions, with an effect similar to
that of a Venus flytrap.
The new material, a rigid frame composed of metal sulfides, has a negative charge. Its
pores, therefore, attract positively charged ions. This makes it a good candidate for ion
exchange. Scientists found that cesium ions bond to the sulfide walls in the interior of
the structure. This reaction causes the framework to close only on cesium ions, and
prevent them from getting out.
This mechanism has the potential to help speed clean-up at power plants and
contaminated sites. The unique process works over a large range of acidities—an
essential property for cleanup at different sites around the world, where pH can range
“The name of the game in cleaning up nuclear waste is to concentrate the dangerous
isotopes as efficiently as possible,” said Mercouri Kanatzidis, senior chemist, Argonne
National Laboratory. “That’s where this new material does its job.”
- New Material Traps Radioactive Ions Using "Venus Flytrap" Method (471 kB pdf)