4 ms·

The paper: [1] They're still at lab scale in glass. They haven't built a usable system, even a small one. The big claim here is that it doesn't clog; capillary

by Animats 5mo ago

The paper: [1] They're still at lab scale in glass. They haven't built a usable system, even a small one. The big claim here is that it doesn't clog; capillary action moves the salt out of the active area to another area, where some yet to be developed mechanism removes it. That needs to be demonstrated. If they can come up with something that runs for years without clogging or replacing the active material, that's a real advance. Laser surface preparation is known.[2] It's useful for roughening smooth surfaces in a very structured way, in preparation for painting. The result is a smooth paint surface. If you sandblast to roughen, the first paint layer is somewhat irregular. Then you need to sand and paint again to get a smooth surface. Laser roughening has been tried for auto painting, but didn't go mainstream. A good question here is whether commercial laser surface prep systems can make the material this new process uses. [1] https://www.nature.com/articles/s41377-026-02315-4 https://www.nature.com/articles/s41377-026-02315-4 [2] https://www.youtube.com/watch?v=BKYOglHYo_Y https://www.youtube.com/watch?v=BKYOglHYo_Y

Nifty3929 5mo ago
It reminds me of how the Panama canal was built, and actually the first major attempt failed and they gave up. What they learned for the second attempt was that digging was not the hard(est) part to solve - it was how to move the dirt! So much dirt! Great book on this BTW: Path Between the Seas. I couldn't put it down.
- Animats 5mo ago
  Fragility is a common problem in surface treatments, sometimes called "nanotechnology". There are super hydrophobic surface treatments that are very effective. They generate a surface which is a forest of tiny sharp points. The surface tension of water is too high to cling to such a surface. You can make something that just will not get wet. The problem is that the points are fragile, and wear destroys the effect. Another example is ultra black coatings. Those are a forest of tiny black objects arranged so that light gets reflected multiple times and is absorbed. The commercial version is called "Vantablack". It doesn't wear well, but for optical applications such as the insides of camera lenses and telescopes, that's fine.
- pchristensen 5mo ago
  It's such a good book! Like any dad reading history, I have been annoying my family for years with fun facts I learned in that book. David McCullough's other books like The Great Bridge (about building the Brooklyn Bridge) are also great.
  - Nifty3929 5mo ago
    You and I are the same person apparently. Let me tell you about malaria! Or the bends! Or tetanus! Please! Wait, where's everybody going?
    - pchristensen 4mo ago
      Did you know that IBM got its start building the control center for the Panama Canal locks? Did you know that lobbying has been the same since at least the 19th century? That 10% of all of France's population invested in their canal company, but the company was too afraid to tell the people that Panama wasn't flat like the Suez Canal area? And... and... and...
jmward01 5mo ago
This is an interesting tech, but I have big doubts. In the picture you can see some salt coating the surface. Even just a little seems like too much for this type of system. I really hope they can make this work and scale this up.
- Animats 4mo ago
  This is similar to a MIT press release from 2023.[1] That's another passive solar powered desalinization system that supposedly doesn't clog with salt. The author's paper list has the 2023 paper, but no followup.[2] Another MIT paper on desalination from 2024 has a more conventional electrically powered system that can adjust its operating speed depending on how much power is coming in. So it can run off intermittent power sources such as its own solar panels.[3] Rather than buffering the energy with batteries, just buffer the water in a tank. This made it to field test and has some efficiency numbers. It's annoying to see these one-off announcements with no followup. A short note a year later reporting why there's no further work would be useful to later workers. [1] https://news.mit.edu/2023/desalination-system-could-produce-freshwater-cheaper-0927 https://news.mit.edu/2023/desalination-system-could-produce-... [2] https://drl.mit.edu/publications/journal/ https://drl.mit.edu/publications/journal/ [3] https://www.greenmemag.com/science-technology/breakthrough-mit-technology-turns-sunlight-into-drinking-water-without-battery-storage/ https://www.greenmemag.com/science-technology/breakthrough-m...
- KaiserPro 4mo ago
  The crucial part is that pressure from the capillary action pushes the concentrated brine out onto the non capillary area. unlike fabric the area isn't enclosed so cleaning is easier if the salt starts to accumulate. Obviously it needs to be cleaned regularly otherwise the salt encroaches into the sensitive bits. However the cleaning method doesn't require dissolving, just scraping.

by Animats 5mo ago

Nifty3929 5mo ago

It reminds me of how the Panama canal was built, and actually the first major attempt failed and they gave up. What they learned for the second attempt was that digging was not the hard(est) part to solve - it was how to move the dirt! So much dirt! Great book on this BTW: Path Between the Seas. I couldn't put it down.

Animats 5mo ago
Fragility is a common problem in surface treatments, sometimes called "nanotechnology". There are super hydrophobic surface treatments that are very effective. They generate a surface which is a forest of tiny sharp points. The surface tension of water is too high to cling to such a surface. You can make something that just will not get wet. The problem is that the points are fragile, and wear destroys the effect. Another example is ultra black coatings. Those are a forest of tiny black objects arranged so that light gets reflected multiple times and is absorbed. The commercial version is called "Vantablack". It doesn't wear well, but for optical applications such as the insides of camera lenses and telescopes, that's fine.
pchristensen 5mo ago
It's such a good book! Like any dad reading history, I have been annoying my family for years with fun facts I learned in that book. David McCullough's other books like The Great Bridge (about building the Brooklyn Bridge) are also great.
- Nifty3929 5mo ago
  You and I are the same person apparently. Let me tell you about malaria! Or the bends! Or tetanus! Please! Wait, where's everybody going?
  - pchristensen 4mo ago
    Did you know that IBM got its start building the control center for the Panama Canal locks? Did you know that lobbying has been the same since at least the 19th century? That 10% of all of France's population invested in their canal company, but the company was too afraid to tell the people that Panama wasn't flat like the Suez Canal area? And... and... and...

jmward01 5mo ago

This is an interesting tech, but I have big doubts. In the picture you can see some salt coating the surface. Even just a little seems like too much for this type of system. I really hope they can make this work and scale this up.

Animats 4mo ago
This is similar to a MIT press release from 2023.[1] That's another passive solar powered desalinization system that supposedly doesn't clog with salt. The author's paper list has the 2023 paper, but no followup.[2] Another MIT paper on desalination from 2024 has a more conventional electrically powered system that can adjust its operating speed depending on how much power is coming in. So it can run off intermittent power sources such as its own solar panels.[3] Rather than buffering the energy with batteries, just buffer the water in a tank. This made it to field test and has some efficiency numbers. It's annoying to see these one-off announcements with no followup. A short note a year later reporting why there's no further work would be useful to later workers. [1] https://news.mit.edu/2023/desalination-system-could-produce-freshwater-cheaper-0927 https://news.mit.edu/2023/desalination-system-could-produce-... [2] https://drl.mit.edu/publications/journal/ https://drl.mit.edu/publications/journal/ [3] https://www.greenmemag.com/science-technology/breakthrough-mit-technology-turns-sunlight-into-drinking-water-without-battery-storage/ https://www.greenmemag.com/science-technology/breakthrough-m...
KaiserPro 4mo ago
The crucial part is that pressure from the capillary action pushes the concentrated brine out onto the non capillary area. unlike fabric the area isn't enclosed so cleaning is easier if the salt starts to accumulate. Obviously it needs to be cleaned regularly otherwise the salt encroaches into the sensitive bits. However the cleaning method doesn't require dissolving, just scraping.