Coated cloth soaks up uranium from seawater for nuclear fuel

The Earth's oceans contain an estimated 4bn tonnes of uranium ions, which could provide a sustainable source of fuel for nuclear power if they could be safely extracted.

New research from China published in the journal ACS Central Science describes a new material for use in electrochemical extraction that can attract uranium ions from seawater more efficiently than existing methods. 

That's vital, because while uranium ore deposits are finite, there's more than 1,000-times more in the sea than on land. Rui Zhao, Guangshan Zhu and colleagues wanted to develop an electrode material with lots of microscopic nooks and crannies that could be used in the electrochemical capture of uranium ions from seawater.

They began with a flexible cloth woven from carbon fibres, which they coated with two specialised monomers. Then they treated the cloth with hydroxylamine hydrochloride to make amidoxime groups, which settled inside the natural porous structure of the cloth, creating pockets that could trap the uranyl ions.

By using the cloth as a cathode, with a graphite anode, and running a current between them, researchers were able to extract uranium, which precipitated as yellow deposits. 

They tested the technique using seawater collected from the Bohai Sea off the coast of China, and found that the electrodes extracted 12.6 milligrams of uranium in 24 days, higher than most other materials tested by the team. It was also three times faster than allowing the ions to naturally accumulate on the cloth. The researchers say their work could open the oceans up as a new source of nuclear fuel.