SEOUL -- Researchers have developed a technique to magnetically separate cesium-137, a radioactive isotope, from soil contaminated with radiation. The affordable method can be used for the decontamination of soil at disused nuclear power plants.
Cesium-137 is formed through the nuclear fission of uranium-235 and other fissionable isotopes in nuclear reactors and nuclear weapons. Cesium-137 fuses with clay, which accounts for up to 30 percent of natural soil, to contaminate the land. The extraction of the radioactive isotope from the soil is a time taking and costly process.
The state-run Korea Atomic Energy Research Institute (KAERI) said in a statement on June 23 that its research team has developed a magnetic separation technique to selectively extract cesium-137 from soil contaminated by radiation.
"The newly-developed soil decontamination technique can be easily commercialized as it uses low-energy magnetic separation technology," KAERI researcher Kim Il-kook was quoted as saying. "We will be able to use this method to decontaminate soil from deconstructed nuclear power plants in the future."
The technique uses the characteristics of clay which has a surface covered with negative electric charges. Positively charged nanoparticles are used to selectively fuse with clay. Fused clay is separated from the soil matter to be washed with a special solution including a positively charged absorbent designed to remove cesium-137. When the clay is washed with the special solution, up to 95 percent of the radioisotope was removed.
Because the method only uses magnetic forces and a special solution for the extraction process, it is affordable. Researchers said that the cesium-removing technique can be upgraded to remove other materials such as heavy metal, oil, and other pollutants from the soil.
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