Science

Electrified cloth extracts uranium from seawater

Cathode showing accumulation from uranium-spiked water
ACS
Cathode showing accumulation from uranium-spiked water
ACS

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

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7 comments
Chase
I know it's far too early in the research to answer the question... but how much power did that 24 days of electrolysis require and how much power could be generated by that 12.6 micrograms of uranium?
wayne247
Could this method be used to extract other metals as well? Could it be used to purify radioactive waste, such as all that contaminated seawater at Fukushima in Japan?
rgbatduke
12.6 milligrams is pretty decent, but big question is -- what was the concentration in the water? In seawater, it will be next to nothing.
Wombat56
Chase, if it's just supplying a few electrons to the positive uranyl ions it may not need much current. It's not like the process is splitting the water.
Nelson
This was Fritz Haber's dream except he wanted gold.
fen
@rgbatduke the page says it was using "natural sea water", at a rate of 5L an hour, and it got 96% of the uranium.

To the others, the data says they used -5 to 0 volt, at 400hz, although I couldnt see anything in the document like "We used 1kwh, to produced uranium capable of 400kwh", But lets put it this way, even if it takes more energy to take the uranium out, it still could be a key to the future, as long as we use something like wave energy to extract it. We are currently wasting a lot of energy putting wave energy into batteries to store for when we need, if we viewed the uranium as a battery, then if it cost 1kwh, to get 0.8kwh of uranium, thats still something we should be interested in, as that 0.8kwh would be on demand whenever we wanted it, once transported to the power plant. We could put it to the side for a hundred years and it would still have the 0.8kwh in it. Thats just my opinion.
MCG
Great news! Let's what we can out of the water, and possibly protect our food chain to boot. Looks like a job for abundant and steady wave power.