New material could unlock vast reserves of nuclear fuel from seawater

Oceans, enveloping the majority of Earth’s surface and fostering an immense array of life, also harbor a dispersed population of uranium ions. These ions, if effectively extracted from seawater, could serve as a sustainable fuel source for generating nuclear power. A recent publication in ACS Central Science unveils a novel material designed for electrochemical extraction, demonstrating enhanced efficiency in attracting elusive uranium ions from seawater compared to existing methods.

Nuclear power reactors tap into the inherent energy stored within atoms, converting it into heat and electricity through a process known as fission, where the atom is split apart. Uranium, due to its instability and radioactivity in all forms, has become the preferred element for this purpose. Presently, uranium is sourced from rocks, but as uranium ore deposits are finite, researchers are exploring alternative reservoirs. The Nuclear Energy Agency estimates that over 4.5 billion tons of uranium exist in dissolved uranyl ions in the oceans, surpassing the land-based reserves by over 1,000 times.

Despite the abundance of uranium in seawater, extracting these ions poses challenges. Existing materials lack sufficient surface area to effectively trap the ions. In response, researchers, including Rui Zhao and Guangshan Zhu, sought to develop an electrode material with a myriad of microscopic features for improved electrochemical capture of uranium ions from seawater.

The team initiated the creation of electrodes using flexible cloth woven from carbon fibers. Coating the cloth with two specialized monomers that were subsequently polymerized, they introduced amidoxime groups to the polymers by treating the cloth with hydroxylamine hydrochloride. The cloth’s natural porous structure provided numerous tiny pockets for amidoxime to snugly trap uranyl ions.

In experiments, the researchers placed the coated cloth as a cathode in seawater—either naturally sourced or spiked with uranium. They added a graphite anode and ran a cyclic current between the electrodes. Over time, bright yellow uranium-based precipitates accumulated on the cathode cloth.

Tests conducted using seawater from the Bohai Sea showcased the electrodes’ ability to extract 12.6 milligrams of uranium per gram of water over 24 days. The coated material exhibited a higher capacity compared to many other uranium-extracting materials tested by the team. Moreover, electrochemical trapping of ions proved to be around three times faster than the natural accumulation on the cloths.

The researchers assert that their work presents an effective method for capturing uranium from seawater, potentially opening up oceans as new suppliers of nuclear fuel.

Source: American Chemical Society

Leave a Comment