London, Jan 17 : Researchers at the University of Edinburgh, UK, have forced uranium - a highly unreactive element, into a chemical reaction, thus raising possibilities of developing cleaning agents for nuclear waste, where uranium is prevalent.
According to a report in Nature News, the fact that uranium is made up of uranyl ions, which are incredibly strong, the substance is very soluble in water and mobile. This makes it difficult to clean it up from groundwater.
Adding to this problem is the estimate by the US Department of Energy that in the United States, 2,500 billion litres of groundwater are contaminated with uranium from nuclear-weapons production.
Because of this alarming fact, the development of cleaning agents or uranium 'mops' is very essential.
Though researchers have earlier looked at using bacteria or plants to soak up the element from the contaminated water, a more effective solution might be to get the uranyl ion to react with something that makes it insoluble, so that it drops out of water. In fact, this would make it easier to collect and get out of the environment.
For achieving this reaction, Polly Arnold at the University of Edinburgh, UK, and her colleagues, got around the ion's stubborn unreactivity by trapping it in the mouth-shaped cavity of a large organic molecule.
This arrangement slightly bends the usually rigid uranyl molecule, so that the oxygen atom sticking out of the top of the large complex becomes reactive, and grabs silicon-containing groups chucked into the mixture.
But, the fact that this particular reaction doesn't work in the presence of air or water, it won't be of much use in the environment.
"We can't use these molecules to clean up nuclear waste," said Arnold.
But, this experiment still stands as proof of the principle that the ion can react - which might be turned to use in cleaning in future.
According to Polly Arnold, a better understanding of uranium chemistry is fundamental to waste-disposal techniques. "Everything that challenges our preconceptions about bonding helps us understand the bigger picture," she said.
The system should also help researchers to understand the
chemistry of the similar element plutonium, which is too dangerous
to study in most labs.