Need help with a Science Project (moisture harvesting)

[Dancin'Dog]

I recently came across an intriguing scientific article about a new material that has been developed which can create water by absorbing moisture from the air, even in climates with 15% relative humidity.  The material cost about $2 per kilo, which is said to produce about 6 liters of water per day at 15% RH.  It's an open source paper, and is aimed at being simple enough for DIY.  It provides sources for the materials & describes the formula & the process in detail.  But, it still isn't dumbed down quite enough for me. :(  I can grasp most of it, but will need a little help to actually try it. 


Here's the link:  [size=78%]https://www.nature.com/articles/s41467-022-30505-2#Fig2[/size]


Take a look and let me know what you think.

[G-dog]

Materials and Method give the ingredients, sources, and recipes.  I did anquick skim of the bigginning of the article through the first paragraph of the M&M.

Most folks don’t have a pH meter or lyophilzer at home - other stuff is pretty easy to substitute with home goods.

Do you have specific questions?

[Watchmaker]

I can help you out with understanding this.

The recipe they describe for the super hygroscopic polymer films is pretty simple:

Start with a 10 mL solution of 0-2.0 weight % hydroxypropyl cellulose in water (all these numbers can be multiplied to make a larger batch, but mixing will become more difficult). Add 0.32-0.82 g LiCl powder (lithium chloride). Then add 0.44g of konjac glucomannan powder to that mixture, rapidly mix with a vortex and cast into a shallow dish. Age for 15 minutes at room temperature, then cool for 3 hours in a refrigerator, then freeze dry. Freeze drying requires specialized equipment which is not cheap, but it's possible to build a homemade freezer drier.

All of the chemicals can be purchased from Sigma Aldrich or Amazon. The equipment is slightly specialized, but any university chemistry lab should be able to do this with ease, maybe make a friend at your local school if you want to actually synthesis some?

Link to a Vortex: https://www.scientificindustries.com/vortex-genie-2.html?gclid=Cj0KCQjwwJuVBhCAARIsAOPwGAQHfBezFqicA_keq7mGj8lwDrWForgkBSdXHY_IgLYCNane_regbA0aAvu9EALw_wcB[/url]
Link to Freeze Drier: https://harvestright.com/product/home-freeze-dryer/
Homemade freeze driers: https://www.makeuseof.com/diy-freeze-dryers-you-can-make-at-home/

Warnings
They discuss adjusting the pH of the solution using NaOH (to get higher pH) or HCl (to get lower pH). These are both chemicals that should only be handled by someone with lab safety experience. Unless you are confident you know what you are doing, I would avoid this. There are other, safer options for adjusting the pH (if necessary) you could try first.

Lithium chloride has some toxicity, don't handle it until you fully understand how to do so safety. Check out the SDS (safety data sheet) for more information: https://beta-static.fishersci.com/content/dam/fishersci/en_US/documents/programs/education/regulatory-documents/sds/chemicals/chemicals-l/S25389.pdf

[chemistk]

Watchmaker's post is a good place to start.

Some unorganized thoughts:

-It's a neat idea but curiously (and unsurprisingly), there's no discussion on scalability. This is presumably a fragile matrix and I would imagine that this polymer is going to tear or disintegrate under its own weight after your first water cycle if you were to handle it. If this were to be developed for use in real-world conditions, I'd bet that it would be affixed to a platform that would not inhibit too much water uptake but would also allow for it to be transported easily.

-Scaling also brings the issue of retrieving the water. It's not like you can just whip this out and have a cup of water in an hour. You'll need a means of warming the gel to remove the water, and then a way to collect that water.

-You might run into trouble purchasing these materials. Sigma's not always too keen on sending laboratory grade chemicals to residential addresses, YMMV.

-From a practical perspective, you probably don't need a vortex mixer if you're only making a small amount at home - you could get away with just vigorous shaking in a sealed container.

-However, you will need a scale that's more accurate than your run of the mill kitchen scale. A really nice postal scale might suffice, but you'd be better served by a really cheap lab grade model.

-I don't know off the top of my head what the pH of 'Solution A' should be, but its pH is going to be key to creating a functional gel. pH strips would probably be okay-ish enough to give you a close idea of where your pH is without having to buy a meter.

-Without practice, there's a really good chance that a DIY version of this would yield less than half of the lab-scale version.

-Don't forget that you need to further purify the water.

This is honestly your best shot for trying - any lab at any level will have a balance, vortex mixer, access to acids and bases, and most importantly - someone on hand who can help make sure you're doing what you're supposed to be doing:

The equipment is slightly specialized, but any university chemistry lab should be able to do this with ease, maybe make a friend at your local school if you want to actually synthesis some?

[Dancin'Dog]

Thanks @Watchmaker and @chemistk for taking a look at this and explaining it.  Finding a school lab to work with sounds like the best idea.  What level of school would be likely to have the necessary lab equipment?  It seems like a community college would be the easiest to approach, but I don't know if they usually have science labs. 


I looked at the DIY freeze drier videos and that seems relatively simple.  But after thinking about the scale of just processing 1 kilo of the material it's obvious that vacuum pump & vacuum chambers would need to be pretty large.  The water extraction setup would also need to be pretty large.  One kilo of the SHPF material only yields a few gallons of water per day, so I was thinking that producing enough water for any useful applications would require a number of kilos.  I'm not sure that I totally understand the water extraction process.  It seems to require a little heat, but I'm not sure if it also requires a bit of vacuum too?  As chemistk mentioned, the SHPF material may not be very durable.  The paper didn't seem to say how many cycles it would last. 


This technology seems to potentially be a great solution to the water needs in arid regions.  If I live in a drier climate I'd be a bit more motivated to try it.  I've got a few home projects that I've been putting off for too long already, so I'd better finish them before getting into this.


Thanks again for the replies.  Maybe somebody here who lives in a desert environment will give it a try and tell us about their results. 

[G-dog]

Thanks @Watchmaker and @chemistk for taking a look at this and explaining it.  Finding a school lab to work with sounds like the best idea.  What level of school would be likely to have the necessary lab equipment?  It seems like a community college would be the easiest to approach, but I don't know if they usually have science labs. 


I looked at the DIY freeze drier videos and that seems relatively simple.  But after thinking about the scale of just processing 1 kilo of the material it's obvious that vacuum pump & vacuum chambers would need to be pretty large.  The water extraction setup would also need to be pretty large.  One kilo of the SHPF material only yields a few gallons of water per day, so I was thinking that producing enough water for any useful applications would require a number of kilos.  I'm not sure that I totally understand the water extraction process.  It seems to require a little heat, but I'm not sure if it also requires a bit of vacuum too?  As chemistk mentioned, the SHPF material may not be very durable.  The paper didn't seem to say how many cycles it would last. 


This technology seems to potentially be a great solution to the water needs in arid regions.  If I live in a drier climate I'd be a bit more motivated to try it.  I've got a few home projects that I've been putting off for too long already, so I'd better finish them before getting into this.


Thanks again for the replies.  Maybe somebody here who lives in a desert environment will give it a try and tell us about their results.

Even a high school with a good science program would likely have the equipment.  But I think a research university might be your best bet - the professors often get quite excited about testing new ideas.  Could be some concern about using resources and time that distracts their lab from their own work projects, but if they find a way that it also helps them get some grant funding, it’s a definite win-win.

Water treatment facilities, water utilities may also be a good contact.

[Watchmaker]

Thanks @Watchmaker and @chemistk for taking a look at this and explaining it.  Finding a school lab to work with sounds like the best idea.  What level of school would be likely to have the necessary lab equipment?  It seems like a community college would be the easiest to approach, but I don't know if they usually have science labs. 


I looked at the DIY freeze drier videos and that seems relatively simple.  But after thinking about the scale of just processing 1 kilo of the material it's obvious that vacuum pump & vacuum chambers would need to be pretty large.  The water extraction setup would also need to be pretty large.  One kilo of the SHPF material only yields a few gallons of water per day, so I was thinking that producing enough water for any useful applications would require a number of kilos.  I'm not sure that I totally understand the water extraction process.  It seems to require a little heat, but I'm not sure if it also requires a bit of vacuum too?  As chemistk mentioned, the SHPF material may not be very durable.  The paper didn't seem to say how many cycles it would last. 


This technology seems to potentially be a great solution to the water needs in arid regions.  If I live in a drier climate I'd be a bit more motivated to try it.  I've got a few home projects that I've been putting off for too long already, so I'd better finish them before getting into this.


Thanks again for the replies.  Maybe somebody here who lives in a desert environment will give it a try and tell us about their results.

Even a high school with a good science program would likely have the equipment.  But I think a research university might be your best bet - the professors often get quite excited about testing new ideas.  Could be some concern about using resources and time that distracts their lab from their own work projects, but if they find a way that it also helps them get some grant funding, it’s a definite win-win.

Water treatment facilities, water utilities may also be a good contact.

I agree a local community college or even high school would be able to do this if they have any kind of decent science program. The easiest way to get some help from a larger university would be to find out if they have some kind of public outreach programming--my local research university has open lab nights on a regular basis, somebody involved in one of those would probably be open to helping. I'd also look for non-academic staff to reach out to--lab managers, etc--they often have more free time than the professors.

Regarding the actual technology, I think it's quite likely that the current material degrades pretty quickly with each cycle--that would be common at this stage of research and at the basic research level, durability isn't often one of the aims. If there is real promise to the idea, the research group will likely be applying for additional funding, maybe looking in to spinning off a company to commercialize the tech. Searching for the authors names, and checking out their other publications can be a great way of finding out more. Or emailing them, I find most academics will reply to a polite email.

[G-dog]

You might find some of this stuff if you have a local makers space - lab-grade scale, pH meter. Probably not a lyophilizer.

Professors LOVE to talk about their work.  In fact, its often hard to get them to stop 😀