According to SCMP, Chinese scientists claim to have discovered an effective method for extracting uranium—the heavy metal used as fuel for nuclear reactors—from seawater using electricity.
Specifically, a research team from Northeast Normal University in Changchun, Jilin Province, China, developed an electrode to capture uranium through electrochemical reactions.
They stated that this method is at least three times faster than current extraction techniques and is effective at filtering out impurities in seawater, making it potentially suitable for large-scale applications.
The research team, led by Associate Professor Zhao Rui and Professor Zhu Guangshan, published their groundbreaking findings in the journal ACS Central Science.
China still needs to import uranium to supply fuel for nuclear reactors. (Photo: SCMP)
China is building more nuclear power plants than any other country, but the quality of its uranium ore is low, necessitating imports to fuel its reactors. The ability to extract uranium from seawater could be a game-changer for China.
Uranium has been an essential element for nuclear energy since 1942, when physicist Enrico Fermi constructed the first nuclear reactor in Chicago.
Traditionally, uranium is extracted from terrestrial rock formations, but the finite nature of these mines has prompted scientists to seek alternative sources of uranium. One of the most abundant sources is the ocean, which contains about 4.5 billion tons of uranium—nearly 1,000 times the reserves found on land.
However, extracting uranium from seawater is an extremely challenging task due to its very low concentration, at 3.3 parts per billion, along with the presence of interfering ions in the complex marine environment.
The difficulty of this task is akin to finding a gram of salt in 300,000 liters of freshwater, if not more challenging.
To tackle this challenge, the Chinese research team created an electrode by coating a fabric made of carbon fibers with two monomers (molecules that can react with other molecules to form structures like polymers), which were polymerized to create an electrode material with tiny protrusions and indentations, known as porous aromatic frameworks (PAFs).
PAFs have catalytic sites to convert uranium ions into uranium compounds and adsorption sites to capture these compounds. The porous nature of the carbon fabric also aids in capturing uranium ions.
In a laboratory experiment by Professor Zhu’s team, a coated fabric served as the cathode, while a graphite anode completed the circuit, with an electric current running between them. Over a few days, they observed bright yellow uranium forming on the fabric.
Bright yellow uranium formed on the fabric in the seawater extraction experiment conducted by Chinese scientists. (Photo: SCMP)
According to the research, this electrochemical method can improve efficiency and extraction speed compared to traditional physical adsorption methods.
Professor Zhu stated in the report: “Using the PAF electrode for uranium extraction (PAF-E) demonstrates higher absorption and faster kinetics compared to physical adsorption.”
In another experiment conducted using water from the Bohai Sea, the research team extracted 12.6 milligrams of uranium per gram of material over 24 days.
The scientists noted that this method outperforms most other reported uranium extraction methods.
Tests also indicated that the electrodes remained stable across multiple extraction cycles, despite the presence of competing metal ions in seawater.
Zhu remarked: “This excellent selectivity is due to the alternating current applied to the electrodes, which repels unbound ions.”
He mentioned that these electrodes could provide a more efficient way to separate uranium from seawater, and this research has enhanced the understanding of the mechanisms behind electrochemical uranium extraction.
The research was funded by China’s National Key R&D Program and the National Natural Science Foundation of China.
