A team of scientists from China's Northeast Normal University has developed an electrochemical method for extracting uranium from ordinary seawater that has the potential to supply humanity with an effectively unlimited energy source.
By current estimates, there are about 8 million tonnes of known reserves of uranium on land. That's enough to fuel the world's nuclear reactors for centuries based on current technology, but in the sea there is an estimated 4.5 billion tonnes in the form of dissolved uranyl ions. If we could extract this economically, it would vastly extend our energy future. Even better, as uranium is removed from seawater, more would leach in from the Earth's crust, providing our descendants with over a billion years worth of nuclear fuel at any projected scale.
Led by Rui Zhao and Guangshan Zhu, the Northeast Normal team is looking at a novel way to extract these radioactive riches. Extraction isn't a new idea. In the past, other researchers have looked at using polymer mats, conductive fibers, and other methods. Now, Northeast Normal is looking at a flexible cloth woven from carbon fibers coated with two specialized monomers and treated with hydroxylamine hydrochloride. The porous cloth provides tiny pockets for the amidoxime, which captures the uranyl ions.
The capture itself seems almost like a school chemistry experiment in its simplicity. The cloth was placed in either seawater or a solution of uranyl ions where it acted as a cathode. Meanwhile, a graphite anode was added. When a current was run between the two, bright yellow, uranium-based precipitates accumulated on the cathode cloth in the same way that bronze coats a baby shoe as a parental memento.
In tests, the team reported extracting 12.6 mg of uranium per gram of water over 24 days, which is a higher amount and at a faster rate than other materials tested or simply allowing uranium to naturally accumulate on cloth.
The research was published in ACS Central Science.
Source: American Chemical Society
