Energy

Electrified fibers help pull uranium out of seawater

Electrified fibers help pull u...
Stanford researchers have developed an electrified material that can help harvest uranium from seawater
Stanford researchers have developed an electrified material that can help harvest uranium from seawater
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Chong Liu, one of the researchers on the study, with a carbon-amidoxime electrode, used for electrifying the material to improve its efficiency at capturing uranium from seawater
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Chong Liu, one of the researchers on the study, with a carbon-amidoxime electrode, used for electrifying the material to improve its efficiency at capturing uranium from seawater
Stanford researchers have developed an electrified material that can help harvest uranium from seawater
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Stanford researchers have developed an electrified material that can help harvest uranium from seawater

Controversial as it is, nuclear power remains a viable source of energy as we transition away from fossil fuels toward methods with far smaller carbon footprints. Underground uranium reserves may be on the decline, but the oceans contain billions of tons of the metal, just waiting for us to find a practical way to extract it. To that end, a Stanford team has developed a technique that improves the capacity, rate and reusability of materials that harvest uranium from seawater.

Despite the ongoing issues of radioactive waste disposal and the occasional Fukushima-scale disaster, nuclear energy can be more efficient and relatively cleaner than fossil fuel sources.

"For much of this century, some fraction of our electricity will need to come from sources that we can turn on and off," says Steven Chu, co-author of the study. "I believe nuclear power should be part of that mix, and assuring access to uranium is part of the solution to carbon-free energy."

Australia, Canada and Kazakhstan together account for about 70 percent of the world's uranium production, but for countries that aren't perched atop a rich mine, extracting it from the sea could be an alternative. Unfortunately, the concentrations are far too small to be viable, but the Stanford team is working on improving that.

"Concentrations are tiny, on the order of a single grain of salt dissolved in a liter of water," says Yi Cui, co-author of the study. "But the oceans are so vast that if we can extract these trace amounts cost effectively, the supply would be endless."

Chong Liu, one of the researchers on the study, with a carbon-amidoxime electrode, used for electrifying the material to improve its efficiency at capturing uranium from seawater
Chong Liu, one of the researchers on the study, with a carbon-amidoxime electrode, used for electrifying the material to improve its efficiency at capturing uranium from seawater

In the past, Oak Ridge researchers demonstrated a material that could pull uranium, in the form of uranyl ions, out of the water like a sponge. It did so with the help of plastic fibers coated in a chemical compound called amidoxime, which attracts the ions and holds them to the surface of the fiber. Once the fiber is saturated, the uranyl can be released by chemically treating the plastic, and then refined for use in reactors.

Using a similar system, the Stanford researchers created their own conductive fiber made of carbon and amidoxime, which allowed them to send jolts of electricity through the material to attract more uranyl to each strand. The method improved on the previous system in three key areas: the capacity for how much uranyl the fibers can hold, the speed of ion capture, and how many times each strand can be reused.

During side-by-side tests, in the time it took the existing fibers to become fully saturated, the new conductive material had already captured nine times as much uranyl, and still had room for more. Over an 11 hour period, Stanford's new fibers managed to soak up three times as much uranyl as the previous fibers, and were three times as reusable.

While it's still a long way from making the process practical on a commercial scale, the researchers say this marks a big step forward for that possible future.

"We need nuclear power as a bridge toward a post-fossil-fuel future," says Chu. "Seawater extraction gives countries that don't have land-based uranium the security that comes from knowing they'll have the raw material to meet their energy needs."

The research was published in the journal Nature Energy.

Source: Stanford University

14 comments
zr2s10
I feel like this could be more useful for cleaning up contamination than for electricity generation. Is there a comparison of how much energy is used to capture the uranium vs how much energy can be obtained from that amount? If there's no net gain, it seems best for cleanup duty, but with a useful waste product.
MikeHingle
The vacuum of “empty space” appears to be an energy reservoir of immense capacity that makes nuclear power seem old fashioned. Richard Feynman and others have pointed out that the amount of Zero Point Energy in one cubic centimeter of the vacuum (ambient space) is much greater than the energy density in an atomic nucleus.
GE’s Vision for the Superconductor Industry (stated in 2002) - "Electric generators made with superconducting wire are far more efficient than conventional generators wound with copper wire. In fact, their efficiency is above 99%, and their size about half that of conventional generators … ” http://www.superconductors.org/uses.htm
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If wind power is used for the electricity needed in this system, and possibly hydro-power it could help to reduce the expense of the power costs. Maybe a centrifuge type system to enhance the collection of uranyl after gathering on the fibers.
CliffG
We read, "For much of this century, some fraction of our electricity will need to come from sources that we can turn on and off," says Steven Chu, co-author of the study. "I believe nuclear power should be part of that mix,..." First off nuclear power can't be switch on and off as suggested. Second, nuclear is too expensive compared to renewables combined with pumped hydro or other means of storage. Third, what is the effect of this process, the "jolts of electricity," on life in the ocean. What percentage of the ocean would need to be processed this way to harvest a meaningful amount. Civilian nuclear power is dead, so why is former Secretary of Energy Chu clinging onto it.
KungfuSteve
This is Insanity. So... you want to take low level material thats spread out all over the place in light concentrations... and then capture it into a super-concentrated form, where by oceanic creatures would be fried... meanwhile, the device could easily fail, and be unrecoverable... wreaking catastrophic damages on a global scale.
These Scientists are Out of Control. Absolutely out of their minds.
Even in a "Clean Up" format, which is SEVERELY needed for Fukushima... and probably the continued existence of humanity... This method could be extremely dangerous, and cause more damage than it tries to solve.
There had better be some high level "Devils Advocates" for any attempt at design / builds. So far, Man's track record of making things better... has resulted in some of the most catastrophic and negatively impacting pollution/destruction ... that this world has ever seen.
JA Larson
Or could it extract mercury from ocean?
PhilMorey
I always thought that was the point of fast breeder reactors. You don't need fuel once you start processing your waste
StWils
Cleaning the rapidly increasing amount of water that is being stored in tanks at Fukushima makes a great deal of sense. It will still take a long time to get to the point where water contaminated today can be re-used to cool Fukushima tomorrow. Same thing at Chernobyl Ukraine, Hanford in Washington state, Oak Ridge National labs in Tennesee, Gathering uranyl from the ocean seems a lot less likely to ever be a viable idea. None the less I would prefer to have tools and choices that MAY be useful rather than do little or nothing except rail at an unfortunate disaster.
Douglas Bennett Rogers
Uranium is very depressed right now. I am still waiting for my Uranium Resource stock to come back. Fuel is a very small proportion of cost of nuclear energy. The value of naval reactors is that they can be turned on in seconds, in the event that an ICBM is headed for the carrier.
ljaques
Filtering uranium from seawater -has- to be cheaper than mining it from high-content ore in the ground, right? Yes, where possible, use this process for cleanup, and if possible, find a way to modify it for mercury containment in seawater. I agree with Chu and would rather have nuclear power generation (yes, which can be switched in and out of the grid at will, but the fuel never turns off) than dirty, uranium- and CO/CO2-spewing coal. Go modular for reduced regulation cost. Recycle fuel for far less nuclear waste.