Russian chemists found a method of producing a metal technetium
Russian scientists from RCTU named after D. I. Mendeleev together with colleagues from other institutes found a simple and cheap method for the synthesis of technetium — expensive and highly sought after metal that is practically not found in nature. The study is published in the journal of Electroanalytical Chemistry.
Technetium is a radioactive element that in large quantities contained in spent nuclear fuel. It is widely used in nuclear medicine as a contrast label for diagnostics of internal organs and tumors, but because of the complex process of obtaining it is very expensive.
In addition, for visualization of tissue need not just technetium, and his special, a metastable isotope with a half life of only six hours. Therefore, it is obtained directly in clinics with a portable nuclear generators in which a flow of neutrons are being bombarded molybdenum target.
Russian chemists have proposed to extract the metal from spent nuclear fuel by means of electric current flowing through solutions of technetium.
"The technetium has many oxidation States, and in the mixture obtained after irradiation of molybdenum targets, it is mostly in its highest oxidation state of 7. And to highlight its best in the form of a metal with oxidation state 0 — so with him, then you can do anything" — presented in the press release of the University the words of the first author, Professor Vitaly Kuznetsov.
First of all, the researchers had to establish whether, in principle, electrodeposition of metal technetium. For this they took pertechnetate potassium salt, KTcO4, in which technetium has an oxidation state of 7, and dropped it in a solution of platinum electrodes, which were applied voltage to 1.6 volts.
Of a normal aqueous solution to metallic technetium impossible during electrolysis on the electrode surface film is formed of oxides of technetium, which does not conduct electricity and blocks its further recovery to the metal. Therefore, scientists have picked up another electrolyte instead of pure water used concentrated solutions of acetates, which maintained constant pH and undesirable processes were minimized.
In this environment, the authors were able to recover the technetium to the oxidation state 0 and precipitate it in the form of films on the electrodes. However x-ray spectroscopy showed that the technetium in these films is not in the metal, and the amorphous state.
"The chemistry and especially electrochemistry of technetium investigated very poorly and it was important to show that actually there exists a principle possibility of obtaining a complete electroreduction of technetium, albeit with the precipitation of partially amorphous, not fully metallic coatings," — says Kuznetsov.
Scientists say that while they worked with the real source of technetium — spent nuclear fuel, and with a model composition of KTcO4 in which the technetium is present in the same oxidation state of 7. The same degree of oxidation has a metastable isotope 99Тс for nuclear medicine obtained after irradiation of molybdenum targets.
Now scientists work out new compositions of media for electrodeposition with higher-quality metal coatings technetium.
By the way the metal technetium is another very interesting application. Through nuclear reactions, it is possible to synthesize ruthenium — a precious metal of the platinum group, which are increasingly used in electronics, while its reserves in the earth's crust is extremely limited.