Skip to comments.Flow electrodes may enable large-scale sea water desalination
Posted on 03/28/2013 12:13:11 AM PDT by neverdem
Across the world, millions of people cannot access fresh, clean water. With global populations rising and freshwater supplies regularly becoming overdrawn or contaminated, the ability to purify sea water is becoming increasingly important.
Now, scientists from South Korea have modified a water treatment method called capacitive deionisation, with the aim of desalinising sea water on a large scale. Capacitive deionisation uses an electric field to remove cations and anions from water flowing past two oppositely placed electrodes. The team, led by Moon Hee-Han from Chungnam National University and Dong Kook-Kim from the Korea Institute of Energy Research, have developed flow electrodes from a suspended carbon material. Not only is this approach more energy efficient it does not require a discharge step like conventional capacitive deionisation but it can also be easily scaled-up simply by increasing the number of flow electrodes in the system.
Yury Gogotsi, an expert in capacitive deionization from Drexel University thinks the flow configuration developed by Moon and co-workers addresses one of the key challenges facing the technology: the small size of electrodes electrosorbing salt ions. In theory, a flow electrode can yield an infinite capacity, only limited by tank size, and be used for water desalination on a large scale, supplying drinking water to a population, he says, adding that, although a proof-of-concept has been demonstrated, further development of the electrode suspension could improve efficiency further. Overall, optimization of this system design may be able to provide a new solution for medium- and large-scale water desalination, he says.
Sung-il Jeon et al, Energy Environ. Sci., 2013, DOI: 10.1039/c3ee24443a
Much like what happened in Seattle, the EPA will come in and call salt a pollutant and ban it from being dumped in the ocean. For those who don’t remember the Seattle city government banned salt from being used as a deicer because it would pollute the Puget Sound.
Genetically engineered food was bad enough, now we have electronically engineered water.
Tried this years ago. A friend owned some desal IP and manufacturing.
I suggested electronically binding molecules to a screen.
I explained a windmill type thing and he had a drum in mind with screens.
I think both ideas had merit but, I liked mine best for stripping bound material off the screen.
He went with his idea and never could keep the salt off the screen before it rotated through the sea water again. That lead to clogging.
I still think the windmill would work or loading barrel screens on a conveyor would work.
Surely they must know the salt originally came from the ocean...
FReepmail me if you want on or off my health and science ping list.
What kind of salt were they talking about, sodium chloride or an almost infinite number of ionic compounds?
What’s an IP? I’m not a mind reader. I doubt that many on this forum can read minds.
This was on FR a while ago
It’s about using graphene for desalination .
This will be driven by price.
It would depend on the concentration, of course - enough salt would kill all the marine life in the Sound. But that much salt would wreak havoc on land a lot quicker.
We certainly hope. Otherwise the fuel required would be better spent on transportation of potable water from elsewhere.
From my understanding they won’t remove salt but rather the Sodium and Chlorine atoms will separate out to the cathode and anode respectively. These present a different problem from salt but there are industrial applications to which they could be applied.
From the abstract: "A capacitive deionization process utilizing flow-electrodes (FCDI) was designed and evaluated for use in seawater desalination. The FCDI cell exhibited excellent removal efficiency (95%) with respect to an aqueous NaCl solution (salt concentration: 32.1 g L−1), demonstrating that the FCDI process could effectively overcome the limitations of typical CDI processes. "
Plentiful gas allows the desalinization at lo cost.
If there were any brains in California, there would be new gas on line and plenty of water from the gas fired desalinization plants
Electricity can be a by product
Ideally, yes. But do you really think governments will allow the marketplace to work freely?
they also know lead comes the ground too.
Nope, government always violates the investing rule - “never subsidize your losers”.
Which will be driven by power requirements. Where’s the juice come from? Millions of windmills?
Windmills, millions of acres of solar panels and a ring of wave machines surrounding the country. It will be driven by prices, with the money coming from market success or government slickness.
Lead comes from the ground, but not in its raw form. Salt, on the other hand, just dissolves in the water again. I suppose there may be an issue with local salinity, but I’d have to hear it to believe it.