A team of chemists from Indiana University has developed a new chemical principle which could help create specially engineered molecules that extract radioactive elements from nuclear waste. The method which could significantly reduce the volume of these radioactive materials will also be applicable to “molecules created to extract chemical pollutants from water and soil,” researchers say.

“This work represents a major step forward in the effort to engineer specially designed nanostructures by providing a new, highly accurate method to predict how these molecules will behave in solution,” says lead author Amar Flood, in a news release.

According to researchers, the special molecule, called a cyanostar, consists of a five-sided star-shaped lattice of carbon and nitrogen atoms with an empty center. The shape allows negatively charged molecules such as phosphates and nitrates to break off from their previous host and have them cornered at the empty center. Structures such as the cyanostar are also known as “receptor molecules” because they are specially designed to receive specific molecules.

Researchers say the technology will help in reducing nuclear waste, as well as in removing chloride from water—a part of the process used to convert seawater into freshwater—to eliminate excess chemical fertilizers from soil, or to gather lithium ions used in renewable power.

Researchers Develop ‘Special Molecule’ That Can Remove Radioactive Elements From Nuclear Waste
Picture shows a triazolophane molecule with chloride in the center suspended inside a liquid solution [via IU]
The team also explain that the dielectric constant – measurement of a substance’s ability to stabilize electrical charge – of the solvent regulates the level of attraction between receptor molecules and negatively charged ion molecules. And when they tested their method using the molecule triazolophane — to extract chloride from surrounding molecules, they found they were able to accurately predict the effectiveness of the engineered molecules.

“The current paradigm only works for molecular designs on the drawing board, in theory, ” says Yun Liu, who is the primary researcher responsible for the method. “But we want to make molecules that will work in practice to help solve problems in the real world.”

With the ability to accurately predict the behaviour of molecules in a solution, the team hopes their method will assist in developing highly accurate computer simulations to rapidly test chemically ngineered molecules designed to achieve specific effects. Moreover, as they make progress with their designs, they could significantly reduce the volume of those radioactive materials and promote the long-term storage of nuclear waste.

The study, entitled “Anion Binding in Solution: Beyond the Electrostatic Regime” has been published in the journal CHEM.

Source: Indiana University