RUDN University chemists created traps for radioactive waste

RUDN University chemists have created supramolecules that can “catch” negatively charged particles, anions. These “traps” can be configured, for example, for the disposal of radioactive waste. The results are published in International Journal of Molecular Sciences .

Technetium is a radioactive metal with a half-life of about 200,000 years. This is one of the by-products that are formed during the processing of nuclear fuel. To catch it, complex chemical processes with labor-intensive operations and a large amount of reagents and waste are required. Technetium also tends to form anions – negatively charged particles. They immediately look for a “pair” – positively charged cations. This greatly complicates the process of recycling technetium. One possible solution to the problem came from the field of supramolecular chemistry. Complex molecular complexes can play the role of anion receptors – “traps” for anions. Choosing the right structure of the supramolecule, one can configure it to attach to certain anions. It was these compounds that RUDN University chemists created and showed that they can be used to “catch” technetium in the form of pertechnetate, an anion with technetium.

“The synthesis of receptors that can recognize anions has recently become a major problem. This stimulates the creation of new anion receptors that could revolutionize several areas, including catalysis, sensing, extraction, and anion transport. For example, to separate technetium from radioactive waste. Such problems can be solved by the methods of supramolecular chemistry,” said Alexander Tskhovrebov, PhD, Deputy Director of Joint Institute for Chemical Research, RUDN University.

In previous research, a group of RUDN University chemists created new “building blocks” for supramolecular chemistry based on selenediazoles. Among other important properties, it turned out that they are soluble in the aquatic environment. This made it possible to speak of new compounds as potential ion receptors. To make technetium invaders out of them, chemists modified the structure of the compounds – they replaced chlorine with fluorine.

RUDN University chemists have obtained fluorine-containing selenadiazoles , cations that bind to pertechnetate . As a result, insoluble salts are formed. In addition, chemists have created and described a series of selenediazoles with different structures, which can “trap” other anions. From a theoretical point of view, the results are also of interest because the so-called chalcogen bonds were used for the first time to trap pertechnetate – a special type of bond within a supramolecule that occurs through elements of group 16 of the periodic table.

“To our knowledge, this is the first study in which pertechnetate accepts a chalcogen bond. Our results will be useful for further developments in the field of anion recognition and precipitation involving cationic selenodiazoles . Now we are continuing the synthesis of selenediazoles “tuned” to specific anions, ” said Alexey Artemjev, researcher at the Joint Institute for Chemical Research of RUDN University.