Inspenet, December 17, 2023.
Scientists from Northeast China Normal University have managed to use seawater as a source of uranium , an essential fuel in the production of energy in nuclear reactors. This advance could significantly contribute to the transition towards a zero- carbon energy source.
Amid global efforts to gradually reduce dependence on fossil fuels, nuclear energy is presented as a reliable option to support the electrical grid. While nuclear fusion is still in an early stage of development and requires more research, nuclear fission represents a known and scalable option for energy generation.
Nuclear fission is a process in which energy is released in the form of heat by splitting a larger atom into multiple smaller atoms.
This generated heat can be transformed into electricity that is integrated into the electrical grid to counteract variations in renewable energy generation. Splitting atoms of heavier, naturally unstable elements is easier. Since uranium exhibits this behavior, it becomes the preferred choice as fuel in nuclear fission facilities.
Uranium in sea water
The uranium used as nuclear fuel is extracted from deposits in various parts of the world. The metal must then undergo an enrichment process to reach the level necessary for use in a nuclear power plant.
Despite this, the Nuclear Energy Agency estimates that approximately 4.5 billion tons of uranium are dissolved in sea water , an amount a thousand times greater than what is estimated to exist in terrestrial deposits.
This discovery could represent a practically unlimited source of carbon-free energy if it could be harnessed. In the form of uranyl ions, uranium dissolved in seawater poses a challenge, and researchers Rui Zhao and Guangshan Zhu from Northeast China Normal University set out to extract these ions and develop a material that would facilitate this process.
Successful obtaining of uranium
The scientists used electrochemical extraction and a flexible mesh woven from carbon fibers to produce the necessary electrodes. This mesh was treated with hydroxylamine hydrochloride, which facilitated the incorporation of amidoxime groups into the structure. The porosity of the mesh allowed the amidoxime groups to lodge and capture the uranyl ions.
In the tests, they used the coated mesh as a cathode, while they used a graphite anode and applied an electric current between them. The result was that uranium ions precipitated at the cathode , causing the mesh to take on a bright yellow hue.
After conducting laboratory tests, the scientists carried out experiments with their device using seawater obtained from the Bohai Sea. Over a period of 24 days, the electrodes managed to extract 12.6 milligrams of uranium per gram of water. Interestingly, immersing the fabric in water containing uranyl ions also enabled passive collection of uranium atoms. However, the researchers observed that the use of electrochemical extraction was three times more efficient than natural accumulation.
The researchers are currently working on expanding their approach, with the hope that the world’s oceans could soon become sources of nuclear fuel. The results of this research were published in the journal ACS Central Science .
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