Carbon Nanotubes Excluding Salt from Seawater
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Carbon Nanotubes Excluding Salt from Seawater
1–10 of 18 posts
Re: Carbon Nanotubes Excluding Salt from Seawater
#2Anyone 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?
Re: Carbon Nanotubes Excluding Salt from Seawater
#3Anyone 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?
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.
Re: Carbon Nanotubes Excluding Salt from Seawater
#4Anyone 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?
"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."
Re: Carbon Nanotubes Excluding Salt from Seawater
#5Anyone 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?
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.
Re: Carbon Nanotubes Excluding Salt from Seawater
#6Anyone 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?
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.
Why does everything have to be so economically driven? Clean drinking water should be totally free for everyone, we kinda need it to live
Re: Carbon Nanotubes Excluding Salt from Seawater
#7Earlier quoted context omitted.
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.
Why does everything have to be so economically driven? Clean drinking water should be totally free for everyone, we kinda need it to live
Clean drinking water for drinking, yes. Clean drinking water for industrial (or even irrigation) purposes, no – because putting a fair price on it would appropriately punish those who use it wastefully.
Re: Carbon Nanotubes Excluding Salt from Seawater
#8Anyone 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?
"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."
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.
Re: Carbon Nanotubes Excluding Salt from Seawater
#9Earlier quoted context omitted.
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.
Why does everything have to be so economically driven? Clean drinking water should be totally free for everyone, we kinda need it to live
I wish it were so simple to remove economics from things. Unfortunately, the problem isn't the need (the demand), its the supply. We don't just have unlimited clean drinking water, and as soon as there is a constrained supply, we have to consider how we can divvy it up to meet demand.
Usually that means increasing price, but the what the commenter above was saying is that often we're making it artificially cheaper. Often by either subsidizing things w/ our taxes (hiding the cost), or by not adequately funding the collection, which will eventually cause failure or exhaustion of the supply.
Re: Carbon Nanotubes Excluding Salt from Seawater
#10Earlier quoted context omitted.
"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."
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 effe…
People are far less energy efficient than modern locomotives. (In terms of chemical energy to motion.) So, I am now not sure what you mean.
PS: You can also extract energy by mixing salt and fresh water, so the minimum energy to separate them must be greater than that.