4 ms·

Nanorods: water-oozing material could help quench thirst

43 points by wallflower 10y ago

Aelinsaar 10y ago
This is pretty exciting, and the applications are almost unlimited, and many of them highly marketable. Athletics clothing alone is billions of dollars around the world, but this a key too: ""But before we can put these nanorods to good use, we need to be able to control and perfect their size and shape," added Nune, the paper's other corresponding author." It seems to me that could be a long process, along with the challenges of scaling up manufacturing. Still, at some point, this is going to be a very useful material.
ChuckMcM 10y ago
That is a really fascinating result. It would also explain the mechanism of graphene sieves. One of the really amazing behaviors of graphene is that you can pour water on top of it, and pure water pops out of the bottom[1]. [1] http://phys.org/news/2016-03-revolutionary-graphene-filter-crisis.html http://phys.org/news/2016-03-revolutionary-graphene-filter-c...
- coolsunglasses 10y ago
  So it deionizes the water too? Wow. If this technology does the same, doesn't that imply we'd need to supply people using this as a source of water with electrolytes and minerals for the water?
  - dogma1138 10y ago
    How is it different from desalination where you add some of the salt back in because the water is too pure?
  - ChuckMcM 10y ago
    Mineralizing water is pretty straight forward, treating it to safe drinking levels is much more complex. So if you simplfy 80% of the water treatment facility's job, you can often process significantly more water through it at the same cost.
  - MollyR 10y ago
    I often wonder if this matters anymore, since food has a high amount of salt, and minerals.
    - coolsunglasses 10y ago
      The food in developing countries doesn't necessarily.
- wonkaWonka 10y ago
  Until, of course, it becomes completely clogged. Ultra-fine filters are going to get locked up by debris quickly. Fortunately, you can probably replace a graphene filter quickly with plenty more freely available/easily producible graphene (quality and practicality of diy graphene might be dubiuous), but, considering the clean-room level of filtration, I'd figure you might need LOTS of graphene, and several layers of coarse filtration, before filtering at the nano-scale.
  - personjerry 10y ago
    I don't think we need to drink water THAT pure though. Although, I guess I'm only thinking about the practical application as a water filter, but I imagine it could be useful in purifying water for science.
  - lunchTime42 10y ago
    Is there no way to work a cleaning mechanism into the material? Dry it and static charge?
nsxwolf 10y ago
Can they work the other way - could you build a solid state dehumidifier with these?
- ericflo 10y ago
  They mentioned harvesting water from the air in the article, so yes.
- derefr 10y ago
  Activated charcoal is already a pretty good dehumidifier; this just seems to take the adsorptive properties of high-surface-area carbon one step further by giving the water an easy path "out" once it's adhered and amassed, keeping the carbon from getting "used up." I wonder if a similar thing could be done with silicon nanorods, given the similarity between activated charcoal and silica gel. "Silicon nano rods" sounds a lot like asbestos—and apparently asbestos is adsorptive, just not of water—but asbestos is micro-scale at best. Meanwhile, SiO2 nanotubes apparently exist[1], but don't show any particular adsorptive properties. [1] https://en.wikipedia.org/wiki/Silicon_nanotube https://en.wikipedia.org/wiki/Silicon_nanotube
tener 10y ago
Could someone with appropriate background explain where does the energy to evaporate the water come from?
- deleted 10y ago
  [deleted]
CamperBob2 10y ago
These papers also noted the process was theorized as early as the 1990s by scientists examining crystallized proteins. Back then, scientists noticed they only saw water vapor surrounding hydrophobic sections of protein, while liquid water would surround other areas. The researchers proposed that there was some sort of process that enabled the water caught between hydrophobic protein sections to suddenly vaporize. This seems reasonably obvious, at least in retrospect. Trap a very small number of water molecules in a region where they can't combine with others to form a liquid, and it's reasonable to expect those molecules to simply waft away. A molecule made from two hydrogen atoms and an oxygen atom weighs much less than the diatomic oxygen molecules in the air, so why wouldn't they displace those molecules?

43 points by wallflower 10y ago

This is pretty exciting, and the applications are almost unlimited, and many of them highly marketable. Athletics clothing alone is billions of dollars around the world, but this a key too: ""But before we can put these nanorods to good use, we need to be able to control and perfect their size and shape," added Nune, the paper's other corresponding author." It seems to me that could be a long process, along with the challenges of scaling up manufacturing. Still, at some point, this is going to be a very useful material.

ChuckMcM 10y ago

That is a really fascinating result. It would also explain the mechanism of graphene sieves. One of the really amazing behaviors of graphene is that you can pour water on top of it, and pure water pops out of the bottom[1]. [1] http://phys.org/news/2016-03-revolutionary-graphene-filter-crisis.html http://phys.org/news/2016-03-revolutionary-graphene-filter-c...

coolsunglasses 10y ago
So it deionizes the water too? Wow. If this technology does the same, doesn't that imply we'd need to supply people using this as a source of water with electrolytes and minerals for the water?
- dogma1138 10y ago
  How is it different from desalination where you add some of the salt back in because the water is too pure?
- ChuckMcM 10y ago
  Mineralizing water is pretty straight forward, treating it to safe drinking levels is much more complex. So if you simplfy 80% of the water treatment facility's job, you can often process significantly more water through it at the same cost.
- MollyR 10y ago
  I often wonder if this matters anymore, since food has a high amount of salt, and minerals.
  - coolsunglasses 10y ago
    The food in developing countries doesn't necessarily.
wonkaWonka 10y ago
Until, of course, it becomes completely clogged. Ultra-fine filters are going to get locked up by debris quickly. Fortunately, you can probably replace a graphene filter quickly with plenty more freely available/easily producible graphene (quality and practicality of diy graphene might be dubiuous), but, considering the clean-room level of filtration, I'd figure you might need LOTS of graphene, and several layers of coarse filtration, before filtering at the nano-scale.
- personjerry 10y ago
  I don't think we need to drink water THAT pure though. Although, I guess I'm only thinking about the practical application as a water filter, but I imagine it could be useful in purifying water for science.
- lunchTime42 10y ago
  Is there no way to work a cleaning mechanism into the material? Dry it and static charge?

nsxwolf 10y ago

Can they work the other way - could you build a solid state dehumidifier with these?

ericflo 10y ago
They mentioned harvesting water from the air in the article, so yes.
derefr 10y ago
Activated charcoal is already a pretty good dehumidifier; this just seems to take the adsorptive properties of high-surface-area carbon one step further by giving the water an easy path "out" once it's adhered and amassed, keeping the carbon from getting "used up." I wonder if a similar thing could be done with silicon nanorods, given the similarity between activated charcoal and silica gel. "Silicon nano rods" sounds a lot like asbestos—and apparently asbestos is adsorptive, just not of water—but asbestos is micro-scale at best. Meanwhile, SiO2 nanotubes apparently exist[1], but don't show any particular adsorptive properties. [1] https://en.wikipedia.org/wiki/Silicon_nanotube https://en.wikipedia.org/wiki/Silicon_nanotube

tener 10y ago

Could someone with appropriate background explain where does the energy to evaporate the water come from?

deleted 10y ago
[deleted]

CamperBob2 10y ago

These papers also noted the process was theorized as early as the 1990s by scientists examining crystallized proteins. Back then, scientists noticed they only saw water vapor surrounding hydrophobic sections of protein, while liquid water would surround other areas. The researchers proposed that there was some sort of process that enabled the water caught between hydrophobic protein sections to suddenly vaporize. This seems reasonably obvious, at least in retrospect. Trap a very small number of water molecules in a region where they can't combine with others to form a liquid, and it's reasonable to expect those molecules to simply waft away. A molecule made from two hydrogen atoms and an oxygen atom weighs much less than the diatomic oxygen molecules in the air, so why wouldn't they displace those molecules?