Molecular Venus flytrap could munch nuclear waste

THE molecular equivalent of a Venus flytrap could capture water-borne nuclear waste.

So say Mercouri Kanatzidis and Nan Ding from Northwestern University in Evanston, Illinois. They have synthesised a sulphide-containing material with a flexible structure that mimics the flytrap's jaws.

The structure has "windows" measuring 0.8 nanometres by 0.3 nanometres - just large enough for caesium ions to squeeze through. Once inside, the caesium bonds with sulphide ions, and this changes the material's structure in a way that closes the windows and traps the caesium.

"The trigger for closing the trap comes from the caesium-sulphide interactions in the material," says Kanatzidis. Even if other ions such as sodium are present, they bond so strongly to water molecules that they can't react with the sulphide, he says (Nature Chemistry, DOI: 10.1038/nchem.519).

Kanatzidis thinks the flytrap could be used to trap radioactive caesium at nuclear disposal sites.

It's elegant chemistry, says Alan Dyer at the University of Salford, UK, but it's unclear if it could perform as well as existing mate.