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.
Great book on this BTW: Path Between the Seas. I couldn't put it down.
Totally underrated area for academic pursuits.
At least in the sciences you have access to lots of opportunities you don’t have at bigger name schools.
They set me up in life in a way that I don’t think would have happened elsewhere.
The reason it doesn't actually work is that it is extremely inefficient. Getting water to condense requires you to somehow reject massive quantities of heat. That's fundamental to physics.
Also, literally anywhere a dehumidifier is reasonably effective, is humid and usually doesn't have such dire water problems. Deserts have extremely low humidity and dehumidifiers working in a desert will produce very little water.
Even a good humidifier in a humid environment is burning KW to generate on the order of ten liters of water a day.
There are a couple places on earth that are essentially deserts but have an early morning humid fog roll through regularly, and those places figured out capturing that water in the air long long before we invented the refrigeration cycle.
It is literally cheaper to desalinate.
Maybe you could build giant greenhouses to fill with sea water and let the sun evaporate the water and collect that with a dehumidifier? Still absurdly inefficient. Water has such an obscene specific capacity for heat that any thermal avenue of separating it from something else will use immense energy.
Now you ask: why don't we just recover magnesium from brines if it's so great? Magnesium recovery from seawater isn't that easy: typically you have to treat it with some kind of alkali (often Ca(OH)2), so the cost is dominated by the extraction process (your alkali is consumed!), and you're competing with a pretty cheap ore. But if you have a solid byproduct, instead of a liquid, the options for magnesium recovery might be a lot more efficient, potentially offsetting the cost.
The fourth-most-prevalent ion, sulfate, might also be interesting, at least in a hypothetical post-petroleum future where sulfur as a byproduct of fossil fuel extraction is no longer "free". Sulfate is also annoying to extract from seawater, but again if we have a solid, the rules change.
As for the "table" salt itself, I think we'd quickly saturate (!) the market.
“We collected a total of 9.3 g freshwater along with 0.343 g of sea salt from the ABF-STIC with a 9 cm2 surface area over the course of 9 hours. This is equivalent to generating 10.33 liters m−2 of freshwater and 0.38 kg m−2 of sea salt per day. The salinity of the desalinated water is found well below the WHO and EPA standards for safe drinking water.”
However the enclosure system required looks rather complicated and might be sensitive to external temperature (maybe a solar PV-powered cooling loop would help) and I imagine the cost-per-square-meter of the material is rather high, so this looks more like something for emergency response situations or maybe a desal system for a mega-yacht. If it could be scaled the idea is interesting, maybe as lithium separation from concentrated geological brines?
...except for the huge piles of salt.
If the salt was not waste, surely people would already be extracting it from the brine and the existing methods would also be "without waste".
I would like to read more about this from an authoritative source.
https://www.frontiersin.org/journals/marine-science/articles...
https://www.sciencedirect.com/science/article/abs/pii/S14635...
Or set up an expensive refining operation to get heavy metals, etc out?
Let me check, is that a wonderful battery ? Nope.. A promising fusion ? Neither...
Ok, so this must be the fourth kind of pseudo-wonder discovery that will maybe make it out of the lab in 20 years, if the research team managed to get scraps of funding while VC pick the next way to waste pensioners money.
Anyway, whenever they have desalinated enough water to get each researcher a pint, the round is on me.
> The brine byproduct wreaks havoc on sea life when it’s deposited back into the ocean by raising the salt level and lowering oxygen in the water.
Managing return of concentrated brine should be entirely tractable in the literal ocean.
Ships (with long submerged pipes) would be prone to weather events and generally less reliable than an installed pipe. Perforation would be prone to clogging from build up so a nonstarter I would expect. Adding flex tubing and a relocation robot would be a maintenance headache as well. Not sure there is an easy optimization.
It’s obvious you can safely put salt back into the ocean with enough dilution. I bet a middle schooler could design a system to do it.
This paper is interesting, however, in directly producing crystalline salt, which is lower volume than brine and easier to dispose of, maybe even valuable.
Easy, but not necessarily good for the spot you're pumping concentrated salt back into.
Just make prettier-than-Himalayan salt lamps out of it and sell it to hippies. Easy solution.