In desert trials, next-generation water harvester delivers fresh water from air

June 8, 2018, University of California - Berkeley
The crystal structure of the newest, aluminum-based metal-organic framework, MOF-303, which captures twice as much water as the earlier MOF used in the water harvester. Credit: Yaghi lab, UC Berkeley

Last October, a University of California, Berkeley, team headed down to the Arizona desert, plopped their newest prototype water harvester into the backyard of a tract home and started sucking water out of the air without any power other than sunlight.

The successful field test of their larger, next-generation harvester proved what the team had predicted earlier in 2017: that the harvester can extract drinkable water every day/night cycle at very low humidity and at low cost, making it ideal for people living in arid, water-starved areas of the world.

"There is nothing like this," said Omar Yaghi, who invented the technology underlying the harvester. "It operates at ambient temperature with ambient sunlight, and with no additional energy input you can collect water in the desert. This laboratory-to-desert journey allowed us to really turn water harvesting from an interesting phenomenon into a science."

Yaghi, the James and Neeltje Tretter chair in chemistry at UC Berkeley and a faculty scientist at Lawrence Berkeley National Laboratory, and his team will report the results of the first field test of a water -collecting harvester in the June 8 issue of the journal Science Advances.

The trial in Scottsdale, where the relative humidity drops from a high of 40 percent at night to as low as 8 percent during the day, demonstrated that the harvester should be easy to scale up by simply adding more of the water absorber, a highly porous material called a metal-organic framework, or MOF. The researchers anticipate that with the current MOF (MOF-801), made from the expensive metal zirconium, they will ultimately be able to harvest about 200 milliliters (about 7 ounces) of water per kilogram (2.2 pounds) of MOF, or 3 ounces of water per pound.

But Yaghi also reports that he has created a new MOF based on aluminum, called MOF-303, that is at least 150 times cheaper and captures twice as much water in lab tests. This will enable a new generation of harvesters producing more than 400 ml (3 cups) of water per day from a kilogram of MOF, the equivalent of half a 12-ounce soda can per pound per day.

Optical microscope images of crystals of the newest, aluminum-based metal-organic framework, MOF-303, which captures twice as much water as the earlier MOF used in the water harvester Credit: Omar Yaghi laboratory, UC Berkeley

"There has been tremendous interest in commercializing this, and there are several startups already engaged in developing a commercial water-harvesting device," Yaghi said. "The aluminum MOF is making this practical for water production, because it is cheap."

Yaghi is also working with King Abdul Aziz City for Science and Technology in Riyadh, Saudi Arabia, and its president, Prince Dr. Turki Saud Mohammad Al Saud, on the technology as part of their joint research Center of Excellence for Nanomaterials and Clean Energy.

Super-absorbent MOFs

Yaghi is a pioneer in metal-organic frameworks, which are solids with so many internal channels and holes that a sugar-cube-size MOF might have an internal surface area the size of six football fields. This easily absorbs gases or liquids but, just as important, quickly releases them when heated. Various types of MOFs are already being tested as a way to pack more gas into the tanks of hydrogen-fueled vehicles, absorb carbon dioxide from smokestacks and store methane.

Several years ago, Yaghi created MOF-801, which absorbs and releases water easily, and last year he tested small quantities in a simple harvester to see if he could capture water from ambient air overnight and use the heat of the sun to drive it out again for use. That harvester, built by a collaborator at MIT using less than 2 grams of MOF, proved that the concept worked: the windows fogged up in the sun, though the researchers were not able to collect or accurately measure the water.

That same harvester was transported to the desert earlier this year and worked similarly, though again only droplets of water were generated as a proof of concept.

In desert trials, UC Berkeley scientists demonstrated that their next-generation water harvester can collect drinkable water from desert air each day/night cycle, using a MOF that absorbs water during the night and, through solar heating during the day, releases it to be condensed and collected. Credit: Roxanne Makasdjian and Stephen McNally

For the new paper, the UC Berkeley team—graduate student Eugene Kapustin and postdoctoral fellows Markus Kalmutzki and Farhad Fathieh—collected and measured the water and tested the latest generation harvester under varying conditions of humidity, temperature and solar intensity.

The harvester is essentially a box within a box. The inner box holds a 2-square-foot bed of MOF grains open to the air to absorb moisture. This is encased in a two-foot plastic cube with transparent top and sides. The top was left open at night to let air flow in and contact the MOF, but was replaced during the day so the box could heat up like a greenhouse to drive water back out of the MOF. The released water condensed on the inside of the outer box and fell to the bottom, where the researchers collected it with a pipette.

The extensive field tests lay out a blueprint allowing engineers to configure the harvester for the differing conditions in Arizona, the Mediterranean or anywhere else, given a specific MOF.

"The key development here is that it operates at low humidity, because that is what it is in arid regions of the world," Yaghi said. In these conditions, the harvester collects water even at sub-zero dew points.

Yaghi is eagerly awaiting the next , which will test the aluminum-based MOF and is planned for Death Valley in late summer, where temperatures reach 110 degrees Fahrenheit in the daytime and remain in the 70s at night, with nighttime humidity as low as 25 percent.

Explore further: Device pulls water from dry air, powered only by the sun

More information: F. Fathieh el al., "Practical water production from desert air," Science Advances (2018). DOI: 10.1126/sciadv.aat3198 , advances.sciencemag.org/content/4/6/eaat3198

Related Stories

Super-adsorbent MOF captures twice its weight in water

January 11, 2018

Material chemists in the Kingdom of Saudi Arabia have developed a superporous solid made up of a patchwork of metal ions and organic linkers (a metal-organic framework, or MOF) that can suck up to 200% of its own weight in ...

MOF keeps humidity in the Goldilocks zone

August 7, 2017

A novel porous material can soak up excessive humidity in a room only to release it again when the humidity falls. Now KAUST researchers have devised a metal-organic framework (MOF) material that monitors its own properties.

Recommended for you

Saliva could influence taste preferences

August 20, 2018

Saliva is crucial for tasting and digesting food, but scientists have now found that it may have another, more subtle role. Salivary proteins could be part of a feedback loop that influences how food tastes to people—and ...

Maple leaf extract could nip skin wrinkles in the bud

August 20, 2018

Maple trees are best known for their maple syrup and lovely fall foliage. But it turns out that the beauty of those leaves could be skin-deep—and that's a good thing. Today, scientists report that an extract from the leaves ...

44 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Parsec
5 / 5 (2) Jun 08, 2018
Long distance backpacking in the Sahara anyone?
cardzeus
not rated yet Jun 09, 2018
Optical image without scale bar...
sascoflame
Jun 09, 2018
This comment has been removed by a moderator.
overcurious
3.7 / 5 (3) Jun 09, 2018
Has anyone given thought to what the effects of less water/humidity in the air will be "downwind"?
ZoeBell
Jun 09, 2018
This comment has been removed by a moderator.
jonesdave
4.6 / 5 (9) Jun 09, 2018
The whole thing is a fraud. There simply isn't that much water two square feet of air. Saturated air at 30° C (82°F) can hold about 30 grams (1 ounce avoirdupois) of water per cubic meter of air. They are talking about 2 cubic feet when there are 35.3 cubic feet in a cubic meter. Check out the link. https://www.youtu...RX6pZSns


Errr, did you not think to put t (time) into your equation? Or, having extracted the total amount of H2O available in a parcel of air above the box, then that is it? The water laden air elsewhere fails to enter the device? Does air move?
antialias_physorg
4.6 / 5 (9) Jun 09, 2018
Long distance backpacking in the Sahara anyone?

At 200ml (or 400ml for the upgraded version) for a kilo of weight...I think you'll need to lug quite a bit of stuff around tro cover your water needs in the Sahara.

The whole thing is a fraud. There simply isn't that much water two square feet of air. Saturated air at 30° C (82°F) can hold about 30 grams (1 ounce avoirdupois) of water per cubic meter of air. They are talking about 2 cubic feet when there are 35.3 cubic feet in a cubic meter.

Air flows through this stuff. It doesn't just sit still. Duh.
antialias_physorg
4 / 5 (4) Jun 09, 2018
Long distance backpacking in the Sahara anyone?

At 200ml (or 400ml for the upgraded version) for a kilo of weight...I think you'll need to lug quite a bit of stuff around tro cover your water needs in the Sahara.

The whole thing is a fraud. There simply isn't that much water two square feet of air. Saturated air at 30° C (82°F) can hold about 30 grams (1 ounce avoirdupois) of water per cubic meter of air. They are talking about 2 cubic feet when there are 35.3 cubic feet in a cubic meter.

Air flows through this stuff. It doesn't just sit still. Duh.
DKD
5 / 5 (3) Jun 10, 2018
Long distance backpacking in the Sahara anyone?

Stillsuit of the freeman. All praise Shai Hulud.
humy
5 / 5 (5) Jun 10, 2018
The whole thing is a fraud. There simply isn't that much water two square feet of air.

Which is irrelevant. When an arbitrarily huge 3D volume of air gradually systematically and eventually comes in contact with the relevant 2D surface then there is that much water. So NOT a fraud.
And where did you get that 2 square foot figure from?
From the article;
"...a sugar-cube-size MOF might have an internal surface area the size of six football fields. ..."
Six football fields has considerably more surface area than 2 square foot.
Eikka
4 / 5 (1) Jun 10, 2018
At 200ml (or 400ml for the upgraded version) for a kilo of weight...I think you'll need to lug quite a bit of stuff around tro cover your water needs in the Sahara.


Consider that you could exhale into the device as you're walking around, so there's a continuous source of high humidity air and high rates of air exchange - that could improve the productivity by quite a lot.

Their system is just passive - open the lid, let the device soak up, close the lid, extract water. If there's air being pumped through all the time, there's going to be lots more water in contact with the MOF and instead of cycling it once a day, you can cycle it once an hour.

memekiller
1 / 5 (4) Jun 11, 2018
@jonesdave, @humy... Did either of you actually go to the link and pay attention? Your rebuttals show you didn't bother. If this is a site for the scientifically-minded, we should drink our own soup. Thunderfoot is a real scientist who takes the time to debunk programs based on hogwash science. Your explanation, even if multiplied by two orders of magnitude, wouldn't turn this into an economically-viable endeavor. Apart from the fact that their paper is demonstrably false in its assumptions, what is astounding is the ease with which a team from some of the world's top universities were able to boondoggle some otherwise pretty smart people, including Bill Gates.

Putting on a uniform doesn't make you a policeman. Buying a guitar doesn't make you a musician. Getting a PhD from MIT doesn't make you a scientist. You still have to....wait for it... do the hard work to master the discipline. The signatories to this study should be collectively and individually ashamed. Clear fraud.
jonesdave
5 / 5 (2) Jun 11, 2018
@jonesdave, @humy... Did either of you actually go to the link and pay attention?


Errr, yes, I've got the paper. Which part are you failing to grasp?
granville583762
3 / 5 (4) Jun 11, 2018
This is a genuine scam and a genuine humidity extractor

Is the air calm or mobile in the desert, is it more calm than mobile and is it calmer at 40% humidity at night. It is impractical for a mobile humidity extractor to have electric fans, but still mobile or fixed there's plenty of solar energy for storage and use for electro-chemical humidity extraction.

If this not a scam and is genuine there are a 1000 and 1 ways to extract your water vapour from between the air molecules as this is why this is a scam because by not being imaginative in the use of nano-materials it is not going anywhere commercially! So is out to make a quick buck at the expense of long term sales and so is a scam
jonesdave
3.4 / 5 (5) Jun 11, 2018
So is out to make a quick buck at the expense of long term sales and so is a scam


Idiot. What quick buck? What is for sale?
granville583762
3.7 / 5 (3) Jun 11, 2018
This has to be a low tech device - no electronics
phys.org> the water harvester can extract drinkable water every day/night cycle at very low humidity and at low cost, making it ideal for people living in arid, water-starved areas of the world

This is mobile as indicated by the arid condition, it has to go on the hump of a camel and it has to be low tech obviously or it will not work, has to be fixed and maintained by the materials that are redaly accessible to desert living creatures.

If this device see's anything remotely like a piece of electronics it will fail in desert conditions where failure is not an option.
granville583762
3.7 / 5 (3) Jun 11, 2018
Where do you think the finance comes from, the market place - where else
granville583762> So is out to make a quick buck at the expense of long term sales and so is a scam

jonesdave> Idiot. What quick buck? What is for sale?

If these discoveries and inventions are not introduced commercially in the market place these institutions will be unable to recoup their research cost!
jonesdave
5 / 5 (3) Jun 11, 2018
Where do you think the finance comes from, the market place - where else


I don't have to 'think' where the funding comes from. I can read it at the end of the bloody paper.
granville583762
2.3 / 5 (3) Jun 11, 2018
This is exactly quite a lot in a nutshell jonesdave. you have not actually said where the finance actually comes from.
We are not mind readers and every one reads some different into what is actually written down (interpretation)
I despair when I see the rating system being used as an alternative to commenting as one can sit there as judge and jury without making their opinion known, it is not there to down grade comments whether we agree with them or not.
It is supposedly there for scientific excellence, not to keep your rating high for replying to a stupid comment, as that deserves no rating at all!
jonesdave
5 / 5 (2) Jun 11, 2018
This is exactly quite a lot in a nutshell jonesdave. you have not actually said where the finance actually comes from.
We are not mind readers and every one reads some different into what is actually written down (interpretation)
I despair when I see the rating system being used as an alternative to commenting as one can sit there as judge and jury without making their opinion known, it is not there to down grade comments whether we agree with them or not.
It is supposedly there for scientific excellence, not to keep your rating high for replying to a stupid comment, as that deserves no comment at all!


Read the paper. At the bottom is the acknowledgements, funding, competing interests, etc.
Do I need to copy/ paste it?
granville583762
3 / 5 (4) Jun 11, 2018
You know that is not necessary, it was your own words that were implied.
jonesdave> Read the paper. At the bottom is the acknowledgements, funding, competing interests, etc. Do I need to copy/ paste it?

The amount you have so far discussed on this finance discussion, you could have said at the begging, it is sometimes appropriate to discus rather than refer to someone's else's work as we want to hear your opinion, not a cut and paste, as you still have not said in your own words.
granville583762
3 / 5 (4) Jun 11, 2018
We like to hear your opinion and comments jonesdave, not a whack a mole fest jonesdave.
jonesdave
5 / 5 (3) Jun 11, 2018
You know that is not necessary, it was your own words that were implied.
jonesdave> Read the paper. At the bottom is the acknowledgements, funding, competing interests, etc. Do I need to copy/ paste it?

The amount you have so far discussed on this finance discussion, you could have said at the begging, it is sometimes appropriate to discus rather than refer to someone's else's work as we want to hear your opinion, not a cut and paste, as you still have not said in your own words.


I didn't write the paper! I didn't perform the experiments! What I think is irrelevant. YOU brought up funding. I told you where to find it. What's to discuss? Read the paper, read the supplementary material, watch the videos. If you need any more data or info, the authors are happy to provide it. Although not, perhaps, to people who have accused them a running a scam, based on nothing at all, other than their fevered imaginations.
granville583762
3 / 5 (4) Jun 11, 2018
If you do not want replys to your self making comments on others comment the only option available to you is to refrain from making comments of an idiot nataure
jonesdave> Idiot. What quick buck? What is for sale?
jonesdave
5 / 5 (2) Jun 11, 2018
Do I need to copy/ paste it?


It would appear so!

Funding: We are grateful to the support of Baden Aniline and Soda Factory–Ludwigshafen, Germany, for synthesis and characterization of compounds and King Abdulaziz City of Science and Technology, Saudi Arabia, for water adsorption studies. M.J.K. is grateful for financial support through the German Research Foundation (DFG; KA 4484/1-1). P.J.W. thanks the NSF and the Berkeley Center for Green Chemistry for support via the Systems Approach to Green Energy Integrative Graduate Education and Research Traineeship (1144885).


granville583762
5 / 5 (1) Jun 11, 2018
jonesdave> Idiot. What quick buck? What is for sale?

In my book your comment suggests to me this is not for sale!
jonesdave
5 / 5 (2) Jun 11, 2018
If you do not want replys to your self making comments on others comment the only option available to you is to refrain from making comments of an idiot nataure
jonesdave> Idiot. What quick buck? What is for sale?


If you make an idiotic comment, why wouldn't I call you an idiot? Especially when it appears that you didn't have a clue where the funding was coming from, and likely can't understand the science.
jonesdave
5 / 5 (2) Jun 11, 2018
jonesdave> Idiot. What quick buck? What is for sale?

In my book your comment suggests to me this is not for sale!


At the moment? No, obviously not. Reading the paper would have told you that. If it becomes commercially viable, then maybe the guy who designed the MOF has got a patent. In which case he deserves whatever he gets.
granville583762
3 / 5 (2) Jun 11, 2018
As your cut and paste indicates jonesdave, it is not for sale which is what you said in the begging when you called me an idiot.
jonesdave
5 / 5 (2) Jun 11, 2018
As your cut and paste indicates jonesdave, it is not for sale which is what you said in the begging when you called me an idiot.


So, if I have translated properly, you are now agreeing with me that this isn't for sale, and therefore your comment about it being a scam was ill advised and ill thought out? Yes?
granville583762
3 / 5 (4) Jun 11, 2018
The finance can not be repaid untill it is sold, your original comment jonesdave, has the hall marks of long ingrained battles with Bennie and Cantdrive, its when you do not know your using them in general comments is when you have to worry.
jonesdave
5 / 5 (2) Jun 11, 2018
The finance can not be repaid untill it is sold, your original comment jonesdave, has the hall marks of long ingrained battles with Bennie and Cantdrive, its when you do not know your using them in general comments is when you have to worry.


And what was I replying to?

So is out to make a quick buck at the expense of long term sales and so is a scam


Did you, or did you not, accuse them of running a scam to make a quick buck? If you have such a thin skin, then you shouldn't leave yourself open to ridicule by making such accusations without at least doing a teeny bit of research. Like reading the freely available paper.
granville583762
3.7 / 5 (3) Jun 11, 2018
As your cut and paste indicates jonesdave, it is not for sale which is what you said in the begging when you called me an idiot.


So, if I have translated properly, you are now agreeing with me that this isn't for sale, and therefore your comment about it being a scam was ill advised and ill thought out? Yes?

This is why we want to hear your opinion and not a cut and pastes because it does not actually say, we have to interperate it.
jonesdave
5 / 5 (2) Jun 11, 2018
As your cut and paste indicates jonesdave, it is not for sale which is what you said in the begging when you called me an idiot.


So, if I have translated properly, you are now agreeing with me that this isn't for sale, and therefore your comment about it being a scam was ill advised and ill thought out? Yes?

This is why we want to hear your opinion and not a cut and pastes because it does not actually say, we have to interperate it.


There is nothing to interpret. It is extremely clear.
granville583762
3.7 / 5 (3) Jun 11, 2018
If this was already for sale non of this would have been mentioned jonesdave, it was not for sale and youu already new it was not for sale when you called me an idiot for suggesting it should be for sale.
jonesdave
5 / 5 (2) Jun 11, 2018
If this was already for sale non of this would have been mentioned jonesdave, it was not for sale and youu already new it was not for sale when you called me an idiot for suggesting it should be for sale.


No. If all you had said was "they should be selling this", then I'd have just pointed to the part of the paper where they say that they are a 'step closer' to making this technology practical. However, you then drew the inference that this was a scam.
You might be feeling miffed at being called an idiot, but what about the authors of that paper, or their friends and relatives being all excited that they have made it into the news! And then coming on here and reading that? Now, if it was Randell Mills, that would be different.................
granville583762
3 / 5 (4) Jun 11, 2018
If this was already for sale non of this would have been mentioned jonesdave, it was not for sale and youu already new it was not for sale when you called me an idiot for suggesting it should be for sale.


No. If all you had said was "they should be selling this", then I'd have just pointed to the part of the paper where they say that they are a 'step closer' to making this technology practical. However, you then drew the inference that this was a scam.
You might be feeling miffed at being called an idiot, but what about the authors of that paper, or their friends and relatives being all excited that they have made it into the news! And then coming on here and reading that? Now, if it was Randell Mills, that would be different.................

This is just another bit of research jonesdave that is going to disappear without trace because the market potential is too small for real financial gain.
jonesdave
5 / 5 (2) Jun 11, 2018
This is just another bit of research jonesdave that is going to disappear without trace because the market potential is too small for real financial gain.


If you say so.

granville583762
3.7 / 5 (3) Jun 11, 2018
Which when it was so described, that is what I implying "This is a genuine scam and a genuine humidity extractor" This was a means to genuinly obtain funds for the research grant, I said it was not a scam as this is the genuine article - you have to see the rice bowl in all this finance, jonesdave! Researchers have bills like the rest of us, they have to eat.
granville583762
3.7 / 5 (3) Jun 11, 2018
Which jonesdave, is why this research is going to dissapear without trace, as the researchers move on to their next rice bowl.
memekiller
1 / 5 (3) Jun 12, 2018
@jonesdave, @humy... Did either of you actually go to the link and pay attention?


Errr, yes, I've got the paper. Which part are you failing to grasp?

I was referring to the link to Thunderfoot that sascoflame provided. Did you watch the video? He demonstrates conclusively which parts of the paper are fraudulent. It claims to be something much more than a Peltier device, which is all it is, and no new science at all, except for a new variation on MOF.
jonesdave
5 / 5 (3) Jun 12, 2018
@jonesdave, @humy... Did either of you actually go to the link and pay attention?


Errr, yes, I've got the paper. Which part are you failing to grasp?

I was referring to the link to Thunderfoot that sascoflame provided. Did you watch the video? He demonstrates conclusively which parts of the paper are fraudulent. It claims to be something much more than a Peltier device, which is all it is, and no new science at all, except for a new variation on MOF.


Yes, I watched it. More to the point, I read the comments. Those that appeared to have been written by people who know what they're talking about, explained to him why he was wrong. It would appear that he's got the wrong end of the stick, and almost certainly owes them an apology. On the other hand, he could always publish a rebuttal in the same journal. The method is described in detail, so anyone can replicate the experiment.
barakn
3.7 / 5 (3) Jun 16, 2018
Did you watch the video? He demonstrates conclusively which parts of the paper are fraudulent. It claims to be something much more than a Peltier device, which is all it is, and no new science at all, except for a new variation on MOF.
Thunderp00t was very poorly "debunking" an older version of this technology. There is no Peltier device in the current version. From the current paper's abstract: "A proof-of-concept device for harvesting water at low relative humidity was reported; however, it used external cooling and was not desert-tested. We report a laboratory-to-desert experiment where a prototype using up to 1.2 kg of metal-organic framework (MOF)–801 was tested in the laboratory and later in the desert of Arizona, USA. It produced 100 g of water per kilogram of MOF-801 per day-and-night cycle, using only natural cooling and ambient sunlight as a source of energy."
barakn
3 / 5 (2) Jun 16, 2018
The comments on Thunderp00t's video show that his fans are generally devoid of scientific literacy. One commonly repeated claim can be paraphrased is "desert air is dry," with the implication that no water can be extracted from it because there is no water. The world record for the highest recorded dewpoint was 95.0 deg F at the King Abdulaziz Air Base in Dhahran, Saudi Arabia at 4 PM local time on July 8, 2003. https://www.wunde...res.html

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.