Researchers at Northeast Normal University in China have achieved a breakthrough in tapping seawater as a source of uranium, a vital fuel for nuclear reactors. This development could play a crucial role in advancing the transition to a carbon-free energy source. As the global community seeks alternatives to fossil fuels, nuclear energy is gaining prominence as a reliable method to support the power grid, particularly during periods when renewable sources like wind and solar are not sufficient. While nuclear fusion is still in the early stages of development, nuclear fission remains a well-established and scalable approach for power generation.
Nuclear fission involves the release of energy in the form of heat when a heavier atom is split into smaller ones. This process can be converted into electricity, providing a solution for handling the intermittencies of renewable energy. Uranium, a naturally unstable element, is a preferred choice as fuel for nuclear fission plants and is typically extracted from various ore deposits worldwide. However, researchers from Northeast Normal University identified a vast potential source in seawater, estimating about 4.5 billion tons of uranium, which is 1,000 times more than land deposits.
The researchers, Rui Zhao and Guangshan Zhu, tackled the challenge of extracting uranyl ions, the dissolved form of uranium in seawater. They developed a flexible cloth woven from carbon fibers treated with hydroxylamine hydrochloride to facilitate the addition of amidoxime groups. These amidoxime groups on the cloth effectively trapped uranyl ions during electrochemical extraction. In their experiments, a coated cloth served as a cathode, a graphite anode completed the circuit, and an electric current ran between them. The precipitated uranium ions turned the cloth a bright yellow.
Laboratory tests were followed by trials in seawater from the Bohai Sea, where the electrodes successfully extracted 12.6 milligrams of uranium per gram of water over 24 days. Interestingly, the cloth, when placed in water containing uranyl ions, also passively collected uranium atoms, though electrochemical extraction proved three times faster. The researchers experimented with various materials and found that the treated carbon fiber cloth performed the best.
The success of this method opens the door to the possibility of oceans becoming a significant supplier of nuclear fuel. The next step for the researchers involves scaling up their approach, potentially paving the way for a more sustainable and abundant source of uranium for nuclear power generation.
