Low-cost gel film can pluck drinking water from desert air:
More than a third of the world's population lives in drylands, areas that experience significant water shortages. Scientists and engineers at The University of Texas at Austin have developed a solution that could help people in these areas access clean drinking water.
The team developed a low-cost gel film made of abundant materials that can pull water from the air in even the driest climates. The materials that facilitate this reaction cost a mere $2 per kilogram, and a single kilogram can produce more than 6 liters of water per day in areas with less than 15% relative humidity and 13 liters in areas with up to 30% relative humidity.
[...] "This new work is about practical solutions that people can use to get water in the hottest, driest places on Earth," said Guihua Yu, professor of materials science and mechanical engineering in the Cockrell School of Engineering's Walker Department of Mechanical Engineering. "This could allow millions of people without consistent access to drinking water to have simple, water generating devices at home that they can easily operate."
The researchers used renewable cellulose and a common kitchen ingredient, konjac gum, as a main hydrophilic (attracted to water) skeleton. The open-pore structure of gum speeds the moisture-capturing process. Another designed component, thermo-responsive cellulose with hydrophobic (resistant to water) interaction when heated, helps release the collected water immediately so that overall energy input to produce water is minimized.
Other attempts at pulling water from desert air are typically energy-intensive and do not produce much. And although 6 liters does not sound like much, the researchers say that creating thicker films or absorbent beds or arrays with optimization could drastically increase the amount of water they yield.
The reaction itself is a simple one, the researchers said, which reduces the challenges of scaling it up and achieving mass usage.
Journal Reference:
Youhong Guo, Weixin Guan, Chuxin Lei, et al. Scalable super hygroscopic polymer films for sustainable moisture harvesting in arid environments [open], Nature Communications (DOI: 10.1038/s41467-022-30505-2)
(Score: -1, Troll) by Anonymous Coward on Friday May 27 2022, @02:22PM
This could be useful for fighting the economic climate change.
(Score: 3, Interesting) by Phoenix666 on Friday May 27 2022, @03:12PM (2 children)
I would guess the material is reusable, but the article didn't clarify that. If the cost of the electricity needed to release the captured water from the material is cheaper than treating water available in the environment, then it would be a great option. It might be attractive to those who want to live off-grid in places where there aren't ready sources of clean water, say, on an atoll in the middle of the ocean or a desert.
Washington DC delenda est.
(Score: 4, Informative) by captain normal on Friday May 27 2022, @04:25PM (1 child)
Seems it is able to absorb and release water repeatedly. In the experiment they use a electric heated plate to drive out the water. That could probably be done using solar heating as it only requires a temperature of 60 C (~140 F). The only big energy requirement is in freeze drying the SHPF which seems to indicate a necessary off site facility.
At least the full article is available: https://www.nature.com/articles/s41467-022-30505-2 [nature.com]
It's been four or five years since we've had a water out of desert air, but this one may be the real deal. At least if there is at least 15% humidity in the location where one needs water.
When life isn't going right, go left.
(Score: 2) by Phoenix666 on Sunday May 29 2022, @02:21PM
Thank you for explaining. I scanned the article quickly and missed that mechanism. It seems that if heat drives the water out then they could set it up in a solar still per your suggestion.
Washington DC delenda est.
(Score: 2) by HammeredGlass on Friday May 27 2022, @03:23PM
https://www.nationalgeographic.com/environment/article/desertification [nationalgeographic.com]
(Score: 2) by MIRV888 on Friday May 27 2022, @06:09PM
'The materials that facilitate this reaction cost a mere $2 per kilogram' ≠ the cost of the product.
People will pay an awful lot for water where there is none.
(Score: 2, Interesting) by Anonymous Coward on Friday May 27 2022, @08:13PM
While our basement never floods (it's on limestone rock), it does get humid enough in the summer that we've lost a few stored items to mold. So we run a dehumidifier.
Our experience with dehumidifiers is getting progressively worse -- started out with one from Craigslist that was about a year old (the seller was moving, showed his receipt), it lasted 5 or 6 years. Then a couple of Kenmore units from Sears (rip), one was actually repaired on warranty(!) and they lasted 3-4 years each. Last year we bought a Toshiba and it quit this spring, 13 months after purchase (12 month warranty)...and the web is full of complaints with similar experience. Now we have a Frigidaire with 1 year warranty, we bought an additional 3 year extended warranty (replacement insurance); I'm fully expecting a free replacement after 2-3 years, so my purchase price might get me 4-6 years of service.
If the description in tfa is true, why can't I set up some of this inexpensive gell over my basement laundry tub and let the condensate go down the drain? I'd even be willing to run a fan to keep it well supplied with moist basement air.
(Score: 2, Interesting) by anubi on Saturday May 28 2022, @08:43AM (1 child)
Zeolite is a reusable dessicant.
I remember researching this for a design for solar powered air conditioning. It actually looked viable to me. It actually used water as the working fluid refrigerant. Just like an EVAP cooler. The zeolite just got the water back out of the inside air.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 2, Interesting) by anubi on Saturday May 28 2022, @11:20AM
Oh, yes, the solar powered part...
When the zeolite picks up it's load of water, it is transported outside via rotating disk or belt, to dry out under the sunlight. The water is released, and the zeolite is ready for another absorption of water from inside.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]