Russian scientists have set a record in the laser synthesis of magnetic particles

 

Russian scientists synthesized magnetic iron oxide nanoparticles by laser radiation. The original design of the laser, as well as the optimization of the synthesis conditions have greatly improved the results of foreign researchers, who used the same method to get the same nanoparticles. But the main result is, of course, is that surpassed our foreign colleagues, and opens up the prospect of using magnetic nanoparticles. They can be successfully used in the fight against environmental pollution.

Cleaning up of soil and waste waters against pollution caused by man and his vital functions — is a serious problem of large cities and industrial areas. Engineers and researchers have proposed many ways of solutions, one of which — the use of magnetic sorbents, ie, substances that can absorb pollutants. The presence of the magnetic properties of the sorbent is a big plus because it allows you to avoid the use of labor-intensive operations to separate the waste from the cleaner solution, replacing them with a simple separation using a magnetic field.

Studies have shown that the magnetic iron oxide nanopowder Fe2O3 is an excellent adsorbent of heavy metals such as chromium from various media. Large specific surface area makes it more nanopowder sorbent capacity and by the nanoparticles can be easily controlled by using a magnetic field. In addition, magnetic iron oxide particles have found use in BioCeramics and targeted drug delivery.

Due to the fact that magnetic nanoparticles have great prospects, it is necessary to find effective ways to produce them. The most advanced and versatile method for preparing such powders, according to researchers Institute of Electrophysics, Ural Branch of the Russian Academy of Sciences, a laser synthesis.

With the help of laser scientists of the Institute evaporated target, made by compressing normal commercial non-magnetic iron oxide powder. Then a pair of evaporated target condensed in the flow of carrier gas (air is used in the study and argon) after which the gas stream passed to the different filter elements. Varying the type and gas pressure and the pumping speed, scientists achieved optimal synthesis. Thanks to the original structure made of laser and optimization of synthesis, scientists were able to surpass the achievements of foreign colleagues, to synthesize nanopowders by the same method and have published Results Journal of Magnetism and Magnetic Materials. Our fellow approximately doubled the yield of nanoparticles and eight times the cost of reduced energy of the laser radiation.

Studies on transmission electron microscope revealed that the nanoparticles have a spherical or faceted shape, and the average size was 15.3 nm. The scientists also analyzed the crystallographic structure of nanopowders, which showed the presence of magnetic phases of iron oxides (magnetite and maghemite). However, some investigators also the gas pressure detected in nanopowder metastable iron oxide, which reduced the magnetic properties of the powder.

Further development of methods for the synthesis of magnetic nano will open the way for the creation of new composite materials, media, high-density magnetic recording, as well as methods of cleaning soil and sewage.

The work was supported by the Ural Branch of the Russian Academy of Sciences (Interdisciplinary project "Development of new sorbents based nanocrystalline ferromagnetic materials for natural and waste waters from heavy metal ions").

Source of information:

VV Osipov, VV Platonov, MA Uimin, AV Podkin "Laser synthesis of nanopowders of magnetic iron oxides." Journal of Applied Physics, 2012, volume 82, no. 4.

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