10 ms·
Low-cost gel film can pluck drinking water from desert air
- numtel 4y agoSeems even better than MOF-based approaches [0] The linked self-watering soil article [1] makes me wonder if the material could be used to reverse desertification. [0] https://wahainc.com//smithsonian https://wahainc.com//smithsonian [1] https://news.utexas.edu/2020/11/02/self-watering-soil-could-transform-farming/ https://news.utexas.edu/2020/11/02/self-watering-soil-could-...
- devit 4y agoIsn't this revolutionary for agricultural use? What's the catch?
- UncleEntity 4y ago> What's the catch? Wide scale harvesting of water from the air will change the local climate in unpredictable ways?
- LNSY 4y agoTBF, that's basically how our entire economy runs, so
- qayxc 4y agoOne catch might be that it hasn't been tested at scale. The results are extrapolations from lab testing in a controlled environment. There's quite a number of inventions and breakthroughs that looked great in the lab but never made it to real world applications. Remains to be seen if this approach can work in practice and at scale and what the real-world implications would be.
- seanw444 4y agoSo is this essentially just a non-mechanical dehumidifier? How is there enough water to pluck, when the point of an arid climate is that it's... well, arid? The air is usually as dry as the ground in those places. Or so I thought.
- NickRandom 4y agoTFA mentions some figures in paragraph 2 "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."
- onlyrealcuzzo 4y agoSo for about $26 - you could extract enough water to water a fruit tree indefinitely. Doesn't seem like this would be used for agriculture at scale - but it sure could beat digging a well to get water for a house.
- astroid 4y agoI'm going to copy this comment I saw on slashdot re: this yesterday that seemed to let some of the air out of the whole press release: "The salt mentioned is not table salt, but lithium chloride. Lithium chloride - which makes up a half by weight of the film, and is also in obvious demand for batteries, is $70/kg or so in bulk." I haven't really dug in deep myself, but this is the comment that deflated me when reading about this yesterday, so worth looking into at least imo
- pengaru 4y agoThere's never really 0% humidity in the air, I have a cabin near Joshua Tree and it rarely goes below 10% there. It tends to increase substantially at night too, which maybe something like this can harness then retain through the daytime.
- 4y ago
- dubswithus 4y agoAfter the water is in the gel, how does one get it out? Edit: > 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.
- robinsoh 4y ago"The captured water in the SHPF can be released by >70% within 10 min through mild heating at 60 °C under a wide range of RH (Fig. 3b and Supplementary Fig. 15). This mild heating temperature is realized by introducing the hydrophilic thermoresponsive HPC with optimized molecular weight, concentration, and pH of the initial precursor (Supplementary Figs. 9–14 and Supplementary Table 2)42"
- conductr 4y agoAt scale, this seems awful for desert ecology. Plants and animals have evolved to survive on bare minimum water. The tiny morning dew may be all they get for days/weeks. Now we want to pluck it out before they can get any. It’s certainly an interesting technology and achievement but one that could be easily misused with “unintended consequences”; or so it seems.
- klvino 4y agoThat was my first thought as well, heavy use within an existing desert environment would likely have negative ecological impact. When reading through the article, it has potential application in areas where a local water supply may not be clean enough to drink or lacks sufficient water treatment & filtration.
- buu700 4y agoOn the flip side, could it potentially be a cost-efficient method of dehumidifying cities/towns/villages for human comfort?
- conductr 4y agoCould even replace desalination since humidity has no salt and it is generally occurring in a similar area/climate.
- bushbaba 4y agoAnd dryer air can absorb more water from the nearby sea...so there might not be a huge impact if placed in the right spot
- sandworm101 4y agoHumidity theoretically doesn't contain salt, but air does. Any technology that is harvesting moisture from air will involve large amounts of air. That air contains dust and sea salt which can contaminate the process. Setup a moisture farm to harvest sea breezes and you will have to address a salt problem. In many industries this airborne salt can cause corrosion. Talk to anyone with a classic car in LA/SF, both cities with sea breezes. They don't want to leave them outside too much. That's why the aircraft "boneyards" are all in the interior, across the mountains from the sea.
- silencedogood3 4y ago
- silencedogood3 4y ago
- spenrose 4y agoSource paper:https://www.nature.com/articles/s41467-022-30505-2 https://www.nature.com/articles/s41467-022-30505-2 Extracting ubiquitous atmospheric water is a sustainable strategy to enable decentralized access to safely managed water but remains challenging due to its limited daily water output at low relative humidity (≤30% RH). Here, we report super hygroscopic polymer films (SHPFs) composed of renewable biomasses and hygroscopic salt, exhibiting high water uptake of 0.64–0.96 g g−1 at 15–30% RH. Konjac glucomannan facilitates the highly porous structures with enlarged air-polymer interfaces for active moisture capture and water vapor transport. Thermoresponsive hydroxypropyl cellulose enables phase transition at a low temperature to assist the release of collected water via hydrophobic interactions. With rapid sorption-desorption kinetics, SHPFs operate 14–24 cycles per day in arid environments, equivalent to a water yield of 5.8–13.3 L kg−1. Synthesized via a simple casting method using sustainable raw materials, SHPFs highlight the potential for low-cost and scalable atmospheric water harvesting technology to mitigate the global water crisis.
- burlesona 4y agoThey say this material is cheap and can pull “ 13 liters in areas with up to 30% relative humidity” … Now I’m wondering if you could use this stuff like crazy in hot, humid places and whether (a) it could pull enough water to be useful for drinking or irrigation, and (b) whether it’s possible to “locally” lower the ambient humidity (like the reverse of the urban heat island effect).
- qayxc 4y agoGetting the water out from the spongy material could pose a challenge in hot environments. According to the paper, they use heating (60°C) to extract the water. In hot environments, however, ambient temperatures get quite close to that already (see India at the moment). The answer to b) would be a no. The technique doesn't work in high humidity environments.
- bell-cot 4y agoWith a somewhat different material, optimized for that situation, could this be made to work well in hot, humid environments? If so, then I'm smelling a plausible solar-powered, cheap, modular "emergency life support" system for people threatened by extreme web bulb temperature conditions.
- cookingrobot 4y agoAre you sure it’s the absolute temperature of 60d that matters, or is the requirement that the sponge is hotter than the surrounding air?
- qayxc 4y agoAccording to the paper, it's the absolute temperature that matters. The desorption is optimal at about 60°C to 70°C, meaning the absorption-desoprition cycle wouldn't work anymore if the ambient temperature is too high. The absorption phase took place at 25°C ambient - the provided data suggests that the desorption would dominate over the absorption above about 50°C. In conclusion, if the environment is 50°C or hotter, the sponge cannot absorb much water from the atmosphere, because the kinetics imply that the water would evaporate too quickly.
- CapricornNoble 4y agoHow do I use this to make Dune-style stillsuits? Maybe the gel is attached to a flagpole on your back (large surface area with airflow is what I'm thinking here), like medieval samurai, and your body's movement generates the heat that activates the thermo-responsive cellulose? The water needs to then collect in a built-in hydration bladder (aka Camelbak).
- dwighttk 4y agoNeed something to cool off the human inside the stillsuit
- paulsmith 4y agoGel? What I really need is a droid that understands the binary language of moisture vaporators.
- fallat 4y agoOk so it's a sponge soaked in konjac and then dried? Damn, that is simple. Could easily make this yourself. I don't even see how this is patentable... > renewable cellulose and a common kitchen ingredient, konjac gum, as a main hydrophilic (attracted to water) skeleton (artificial sponges are made of cellulose - I learned this just last year when washing my dishes and thinking... wtf is this made of?) --- Seems then you can: 0. Go to the dollar store 1. Buy a thin sponge 2. Buy konjac gum 3. Buy a tray 4. Place the thin sponge in the tray, mix the konjac gum with water, and pour it into the tray, and place it into your freezer, waiting for the water to evaporate...? 5. Place it now somewhere in a humid place to pull the water out of the air --- Industrial version of this is probably a ton of thin wafers side-by-side in a cube-like fashion, so they can easily come off an assembly line
- bradrn 4y agoIt doesn’t look quite that simple. The paper describes the procedure as follows: > In a typical fabrication, LiCl powder (0.32–0.82 g) is added into 10 mL HPC solution (0–2.0 wt%) forming solution A. The pH of solution A can be tuned by NaOH or HCl solution. 0.44 g KGM powder is added into solution A and quickly cast into the petri dish after vortex. The gelation takes place within 2 min, and sit in room temperature for 15 min. Then, the film is placed in the fridge (−4 °C) for 3 h followed by 15 min freeze in liquid nitrogen. Last, the gel film is ready to use after 12 h freeze-drying. [https://doi.org/10.1038/s41467-022-30505-2 https://doi.org/10.1038/s41467-022-30505-2]
- natch 4y agoDude you don’t have liquid nitrogen in your fridge? Such common kitchen ingredients. /s
- natch 4y ago> researchers used renewable cellulose and a common kitchen ingredient, konjac gum “konjac gum” a common kitchen ingredient, eh? Let me just check my pantry. Odd, seems I am fresh out.
- TrueDuality 4y agoIt is commonly used in Vietnamese cooking. The Konjac plant is kind of like corn. Konjac gum is like corn starch.
- c_o_n_v_e_x 4y agoKonjac noodles are a thing in Japan. They are low carb friendly as well.
- lr 4y agoHow about in wet, hot environments (or even cold ones), like on a boat? Watermakers are very expensive and use a lot of electricity. If one could do this on a boat to generate clean drinking water, that would be pretty amazing. Especially if one could use a tube solar oven to heat up the substance.
- timerol 4y agoThird paragraph of TFA: > The research builds on previous breakthroughs from the team, including the ability to pull water out of the atmosphere[1] and the application of that technology to create self-watering soil[2]. However, these technologies were designed for relatively high-humidity environments. 1: https://news.utexas.edu/2019/03/13/solar-powered-moisture-harvester-collects-and-cleans-water-from-air/ https://news.utexas.edu/2019/03/13/solar-powered-moisture-ha... 2: https://news.utexas.edu/2020/11/02/self-watering-soil-could-transform-farming/ https://news.utexas.edu/2020/11/02/self-watering-soil-could-...
- apienx 4y agoThermal degradation plus oxidative processes make the claimed "scalable" water-capturing application unfeasible IMHO. The authors extract the water by heating to 60 °C. I'm surprised neither the Nat. Comm. editor nor any of the reviewers asked for a thermo-gravimetric analysis of the material.
- mise_en_place 4y agoI’ve been hearing about so-called hydropanels too. Maybe they work similarly? It looked like junk science when I initially saw one producer of these, called Source Global. It seems to be a real thing, however.
- jmyeet 4y agoWith the very real risks of climate change and rising sea levels I'm wondering how long it will take before someone decides to flood the Sahara. It's worth noting that sea level rise is kinda complex. First, if an iceberg floating on the ocean melts it doesn't raise sea levels. That's the buoyancy principle of displacing an object's weight in water. Second, a lot of ice (eg Antarctica, Greenland) is on land so the first point doesn't apply to all ice as some deniers have tried to claim. Third, the sea level rise is partially from ice melt but also from thermic expansion. Fourth, even if you flooded all the below sea level parts of the world, it would only account for a fraction of the sea level rise so it's not a permanent solution. But several thousand eyars ago the Sahara was arable land. Some parts of the Sahara were >400 feet below sea level so this would be a significant body of water. Even as seawater this would inject a lot of water into the environment through evaporation and normal water cycles. Obviously this would have an impact on the ecosystem and displace some people but we've displaced far more people for less (eg the Three Gorges Dam). This seems like something we should do, no?
- sumtechguy 4y agoYou may want to look into what the permaculture people are doing. That is something that can be done today and has worked many times. Many are seeing really good results. The issue for that area is most of the vegetation was clearcut for firewood. Basically with permaculture they try to put the system back to the way it was before it was clearcut.
- bushbaba 4y agoWe'd need to flood it with salt water. Best example as to why this shouldn't be done is the California Salton Sea ecological disaster.
- henearkr 4y agoWhat if we do not flood it, but instead make circulate a lot of salt water in open-roofed canals (but with leak-proof floor and walls) crisscrossing the desert? Then the humidity would trigger rains and help grow a vegetation, and the salt residues would remain inside the canals. Then at some point the vegetation would self-maintain the necessary humidity level.
- samstave 4y agoSHPF == Shit Hits the Proverbial FAN. Would this be viable in a Window Casing/Screen? system where-by you have, instead of a "screen" you have this mesh - then with a window moulding application that funnels the water to either an "ITS ALL PIPES" type of reclaimation..... https://www.youtube.com/watch?v=s09pfBEJYHc https://www.youtube.com/watch?v=s09pfBEJYHc
- WhitneyLand 4y ago$2/kg of material to get 6 liters of water per day. But what’s the total yield for the $2? In other words single or multiple use? In some areas of the world there’s a serious fresh water crises. Very poor people are left buying expensive bottled water to avoid disease.
- rodolphoarruda 4y ago"Proudly made in Arrakis" Fremen Inc.
- 1minusp 4y agoany experts who can verify the validity of the claim of being low cost?
- russellbeattie 4y agoCalifornia's coast is lined with mountains which capture huge amounts of water from the air as it comes in from the Pacific, usually as fog. This is why the redwoods are so massive. I have no idea if this technology works at the scale of Cali's water deficit, but I've wondered why we haven't lined the peaks of the mountains with mesh screens already. Seems like free water we're just ignoring.
- jvanderbot 4y ago"In a typical fabrication, LiCl powder (0.32–0.82 g) is added into 10 mL HPC solution (0–2.0 wt%) forming solution A. The pH of solution A can be tuned by NaOH or HCl solution. 0.44 g KGM powder is added into solution A and quickly cast into the petri dish after vortex. The gelation takes place within 2 min, and sit in room temperature for 15 min. Then, the film is placed in the fridge (−4 °C) for 3 h followed by 15 min freeze in liquid nitrogen. Last, the gel film is ready to use after 12 h freeze-drying. The final LiCl concentration in SHPFs is characterized by TGA." "Before the water vapor sorption measurement, all samples are dried in a vacuum oven at 90 °C for at least 2 h. " - Fridge cooling - liquid nitrogen bath - 12h freeze drying That doesn't sound low-cost / easy to manufacture. https://www.nature.com/articles/s41467-022-30505-2 https://www.nature.com/articles/s41467-022-30505-2 Figure of test rig: https://www.nature.com/articles/s41467-022-30505-2/figures/4 https://www.nature.com/articles/s41467-022-30505-2/figures/4 That looks like you capture using a very cold, porus material (cold, dry sponge that collects dew, essentially), then heat this "sponge" so the water then travels up to a condenser which causes it to "dew" and run into a collection chamber. It's not magic water-cloth, and I don't think it's a weekend project, but it's pretty low tech. What did I get wrong? I'm sure there's something.
- robonerd 4y agoFWIW real "magic water-cloth" actually exists, but only works some places some of the time: https://en.wikipedia.org/wiki/Fog_collection https://en.wikipedia.org/wiki/Fog_collection > The mesh netting is where the condensation of water droplets appear. It consists of filaments knitted together with small openings, coated with a chemical to increase condensation. Shade Cloth is used for mesh structure because it can be locally sourced in underdeveloped countries. The filaments are coated to be hydrophilic and hydrophobic, which attracts and repels water to increase the condensation.[1] This can retrieve 2% of moisture in the air. Efficiency increases as the size of the filaments and the holes decrease. The most optimal mesh netting is made from stainless steel filaments the size of three to four human hairs and with holes that are twice as big as the filament. The netting is coated in a chemical that decreases water droplet's contact angle hysteresis, which allows for more small droplets to form. This type of netting can capture 10% of the moisture in the air.[2]
- ThinkBeat 4y agoIn my experience, just in the US the desert air is really dry. The expression "but it is dry heat", is true. I find hot desert weather much better than hot weather in humid areas. I cant see this scaling. There is not much water to collect to begin with. A person using it sure. A platoon sure. But if a city of 2000 people started using I cant see it working well. Further the moisture extracted from the air in that city would mean even drier air in other places?
- mikepurvis 4y agoAgree, yeah. Despite the lead of "more than a third of the world’s population lives in drylands", I would see this as being much more applicable to transient usage than long term. A few litres of lukewarm water per day would be perfect for backcountry camping, or topping up the reservoir in an RV, or something. But for anywhere even remotely permanent it almost certainly makes more sense to dig a well.
- felipemnoa 4y ago>>Further the moisture extracted from the air in that city would mean even drier air in other places? I imagine moisture from other places would simply travel to his low humidity place to replace the one taken out. Should be limitless.
- Animats 4y agoIt's from U. Texas. Texas has the climate in which that technology should work, and a need for more water. This ought to be fundable and buildable entirely within Texas. When will the first plant be built?
- aaron695 4y ago
- WheelsAtLarge 4y agoDesalinization plants are horrible for the environment. In short they destroy the water environment around them because they dispose of the waste left after the water is extracted from the salt water right back into the ocean. Raising the salt level to a point where few animals can live in the water. My question is can this process be scaled to the point of replacing the standard desalinization plant?
- josephcsible 4y agoOceans are big, and there's no barriers to diffusion. Why would the extra salt be concentrated enough to cause a problem?
- WheelsAtLarge 4y agoIt is hard and expensive to diffuse the brine that's left after the freshwater is extracted. The whole ocean is not affected but it's the area around the plant. Which can be a very large. https://www.scientificamerican.com/article/slaking-the-worlds-thirst-with-seawater-dumps-toxic-brine-in-oceans/#:~:text=But%20desalination%20plants%20are%20energy,underground%20or%20spread%20on%20land https://www.scientificamerican.com/article/slaking-the-world....
- miguelmichelson 4y agoThis is happening in the driest desert in the world, this is a simpler but effective technique to get water out of the desert fog https://youtu.be/w5cBSORuB6w?t=35 https://youtu.be/w5cBSORuB6w?t=35
- c_o_n_v_e_x 4y agoSeems like this could have potential for recovering water that you intentionally evaporate such as evaporative cooling towers