Carbon Nanotubes Excluding Salt from Seawater

https://www.sciencedaily.com/releases/2017/08/170824182653.htm

by meri_dian • 9 years ago

82 17 9 years ago

Anyone read the paper to see what kind of flux this technology might have compared to materials used in existing membranes?

I often hear about desalination as an energy problem, since the plants use so much to run. I'd be interested to know if this technology would lower the energy requirements of desalination. Anyone read the paper?

valuearb• 9 years ago

The real problem is that clean drinkable water is often given away almost for free. California, for example, reserves vast amount of available water for specific groups, instead of having a market where a higher price would not only directly drive conservation, but would make things like desalination more attractive.

damnfinecoffee• 9 years ago

Why does everything have to be so economically driven? Clean drinking water should be totally free for everyone, we kinda need it to live

Dylan168072• 9 years ago

"because osmosis is a simple matter of thermodynamics, it's possible to calculate exactly how efficient we can make the process. And, as it turns out, we're really quite close as these things go. A state-of-the-art facility is now within a factor of two of the theoretical energy minimum, and only 25 percent higher than the realistic minimum for the current reverse osmosis process."

claudius2• 9 years ago

Hm, I’m not sure I buy this argument, as it relies on the entire procedure being in equilibrium at all times. For the same reason that the human body can operate at much higher efficiency than a steam locomotive (or even the "perfect" Carnot engine), it should be possible to devise a desalination process which is much more efficient than the thermodynamic optimum by relying on catalysts and other non-equilibrium effects.

prestonh• 9 years ago

Haven't read the paper, but the large energy requirements for desalination right now come from the rough interiors of the channels creating large frictional forces which resist the flow of water. Carbon nanotubes don't suffer that drawback.

ResearchAtPlay• 9 years ago

Perhaps this membrane is also interesting for electricity production. From the abstract:

CNTPs block anion transport, even at salinities that exceed seawater levels

High salinity levels that occur in some mining processes could produce electricity via pressure-retarded osmosis. Reaching adequate flow rates through membranes has been a barrier to this tech in the past [1].

As a slightly off-topic question: Does anyone know of any industrial processes where high volumes of fluids with high salinity concentrations occur? I am doing some research on where this technology could be applied.

[1] www.nature.com/articles/nature11477

Carbon Nanotubes Excluding Salt from Seawater

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