For cryogenics we use zeolite for drying our process gases. There are different types of zeolite. Our canisters contain silica gel beads for color indication of saturation. The zeolite is such a strong desiccant that it will pull moisture out of the silica gel. Now it might be that by weight silica gel is better, but it's my understanding that zeolite is capable of drying out a gas to a much greater degree. It's also possible you got counterfeit zeolite or an unsuitable grade of zeolite. Also, we regenerate our zeolite using heat and a vacuum pump in concert to get it extremely dry.
Zeolite will continue pulling moisture at MUCH lower humidity levels. Silica gel can hold more total, but it equalizes with ambient humidity at a much higher humidity level. Zeolite will keep pulling until there's nothing left, or the zeolite is saturated.
Absolutely. Zeolite works in a pressure swing drier. We used it for an infrared camera that was cooled to cryo temperatures. The slightest moisture would have ruined it, but the pressure swing zeolite produced absolutely dry air.
@@blueredbrick The blue ones don't contain copper. They contain cobalt chloride. The orange ones contain methyl violet. Both are much more toxic than copper. But yes, don't eat them, but also know they do leave residue of the color changing material on whatever they touch, especially when heated.
@@dl200010 oh cobal? Interresting . My mistake. Never knew it was cobalt based. I mistakingly assumed (or though so reading about it long ago) t must have been copper. Ps, I find it an interesting topic so I went into the rabbit hole of looking up the different versions and history etc. It appears that in the EU cobalt indicator is no longer allowed for kitty litter, and a methyl blue due is used and the in version I only ever saw are the packages with mostly clear amorphous kistals/chunks with on a few blue with a hint of green colored ones, but after looking at the different products offered I learned that all blue packages silica kitty litter is also being sold but never saw that here. But no copper based dyes in any case or nickel for that matte.tnx for pointing that out. Learnt a few things. My cats do not like it so never noticed the silica with added methyl dye leaving staines. that is a typical nuisance voiced by reviewers of brands sold here. I do not expect the cobalt versions to leach out of the silica matrix. good news overall. Found some loopholes to get the cobalt versions (that I no longer approver of btw even when it is nice to look at). I also found a brand here that leaves out any form of wet indicator and is pure amporhous silica. That also is good news; cheap acces to a good drying material without impurities.
@@dl200010 It appears that the cobalt version is no longer being sold in the EU here, went on a google search and its interesting. Tnx for pointing this out. We have both pure clear silica litter and clear and a few blue colored ones in the mix based on a version of a.methyl blue due like youwntioned. Never saw the orange ones but did not go looking those tbh in the stores. I'm happy to have found a brand that leaves out any fragrant or indicator dyed beads. Cheers.
I think the advantage of zeolite/molecular sieves is not how much it holds, but how aggressively it can pull water out of low humidity air or solvents. Calcium chloride would've been an interesting candidate too.
Don’t quote me on this (he says while typing on the internet) but I recall reading that cooking rice, or any starch really, crosslinks the sugars and starches making them absorb less water than raw, hulled rice. Also, different desiccants must be heated to different temperatures to drive off the most water. Just taking them to the in-air boiling point of bulk water can’t push out the intercalated water from clay grains. Also also, doing that fundamentally changes the structure of most kinds of clay from the hydrated forms. Therefore their densities and water absorption properties can change quite a bit depending on the drying temperature. It’s been a long time since I had anything to do with desiccants, so your mileage may vary.
I wonder where that cross linking action would come from, in my mind which is definitely not to be quoted i would have expected the opposite, cleaving action.
Getting water past it's phase change temperature will release it from any material not chemically bonded to it. It's only a matter of time. To properly dry out bentonite clay, a temperature range of **150°C to 200°C** (302°F to 392°F) is recommended. This range is effective for removing moisture without damaging the clay's molecular structure or properties[1][2]. Drying bentonite at higher temperatures, such as those above 500°C (932°F), can irreversibly remove crystallization water and degrade the clay, turning it into a non-functional aggregate[2]. For industrial purposes, rotary drum dryers are often used to achieve the necessary moisture reduction, typically bringing the moisture content down to between 5% and 12%[2]. It is crucial to control the drying process carefully to maintain the quality and functionality of the bentonite clay. Citations: [1] www.sciencedirect.com/science/article/abs/pii/S0169131717304222 [2] www.ftmmachinery.com/blog/bentonite-processing-process-and-equipment.html [3] kegriver.com/the-importance-of-moisture-content-in-bentonite-sulfur-clay/ [4] library.csbe-scgab.ca/docs/journal/30/30_2_237_ocr.pdf [5] temaprocess.com/2020/drying-bentonite-clay-using-tema-process-fluid-bed-dryer/ [6] www.wyomingsunmade.com/sun-drying_23.html [7] www.medicalnewstoday.com/articles/325241 [8] digitalfire.com/material/bentonite [9] skyorganics.com/blogs/blog/5-ways-to-use-indian-healing-clay-bentonite-clay [10] www.mnclay.com/AddToCart2.aspx?ProductGroup=BENT [11] www.reddit.com/r/HaircareScience/comments/fuc42n/how_using_bentonite_clay_has_saved_my_fine_oily/ [12] www.douyee.com/en/products/item/566/clay-desiccants [13] homedistiller.org/forum/viewtopic.php?t=68673 [14] www.happyherbalist.com/bentonite-clay-8-oz/ [15] blog.biokeram.com/bentonite-in-my-formula-how-to-dry-faster [16] www.silica-gel.it/en/content/12-activated-clay
"but I recall reading that cooking rice, or any starch really, crosslinks the sugars and starches making them absorb less water than raw, hulled rice." There is no sugar in rice. Cooking converts rice to gelled form. One type of rice, called boiled rice (or parboiled rice) has been cooked and then dried. Puffed rice is the preferred desiccant. "Just taking them to the in-air boiling point of bulk water can’t push out the intercalated water " right; zeolites are clay with pores. If you soak the beads in water (saturate it) and then remove the external water by heating around 100C, you will get an idea of bound water. Most of the zeolites are lab made these days (bentonite is natural)
@@janami-dharmam Starches are just complex sugars. Repeated cooking of starches does change their chemical properties: ## How Re-Cooking Changes the Structure of Starches in Potatoes and Rice The process of cooking, cooling, and reheating starchy foods like potatoes and rice significantly alters the structure of their starches. This transformation primarily involves two key processes: **gelatinization** and **retrogradation**. ### **Gelatinization** When starchy foods such as potatoes and rice are cooked, the heat causes the starch granules to absorb water and swell. This process, known as gelatinization, disrupts the crystalline structure of the starch molecules, primarily amylose and amylopectin, making them more digestible. During gelatinization: - The starch granules absorb water and swell. - The crystalline structure of the starch breaks down. - The starch becomes more accessible to digestive enzymes in the small intestine, converting it into glucose more readily[2][5]. ### **Retrogradation** After the cooked starches are cooled, a process called retrogradation occurs. During retrogradation: - The amylose and amylopectin chains realign and form a new crystalline structure. - This new structure is more resistant to digestion, hence the term *resistant starch*. - Resistant starches pass through the small intestine undigested and reach the colon, where they act as prebiotics, feeding beneficial gut bacteria[1][3][6]. ### **Reheating** Reheating these cooled starches can partially disrupt the crystalline structure formed during retrogradation. However, not all resistant starch is broken down: - Reheating can decrease the amount of resistant starch slightly, but a significant portion remains intact. - The reheated starches still exhibit lower digestibility compared to freshly cooked starches, leading to a reduced glycemic response[1][2][9]. ### **Health Benefits** The formation of resistant starch through this cooking-cooling-reheating cycle offers several health benefits: - **Improved Glycemic Control**: Resistant starch does not raise blood glucose levels as much as digestible starch, which helps in managing blood sugar levels[1][6]. - **Enhanced Gut Health**: Resistant starch acts as a prebiotic, promoting the growth of beneficial gut bacteria and producing short-chain fatty acids like butyrate, which are beneficial for colon health[2][3]. - **Increased Satiety**: Foods high in resistant starch can increase feelings of fullness, which may aid in weight management[3]. ### Practical Applications To increase the resistant starch content in your diet: - Cook starchy foods like potatoes, rice, and pasta. - Cool them in the refrigerator for at least 12-24 hours. - Reheat them before consumption if desired. Reheating does not significantly reduce the resistant starch content[1][3][9]. In summary, the re-cooking of starches in foods like potatoes and rice involves the processes of gelatinization and retrogradation, which alter the structure of starch molecules, making them more resistant to digestion and offering various health benefits. Citations: [1] www.healthline.com/nutrition/cooling-resistant-starch [2] www.bernard-preston.com/Reheating-resistant-starch.html [3] hopkinsdiabetesinfo.org/what-is-resistant-starch/ [4] www.sciencedirect.com/science/article/abs/pii/S0268005X20329179 [5] chemistry.stackexchange.com/questions/116895/does-cooling-a-potato-change-the-nature-of-its-carbohydrates [6] pubmed.ncbi.nlm.nih.gov/26693746/ [7] www.sciencedirect.com/science/article/pii/S0023643895945520 [8] www.ncbi.nlm.nih.gov/pmc/articles/PMC7984060/ [9] www.nytimes.com/2023/11/08/well/eat/resistant-starch-pasta-rice-leftovers.html [10] www.ncbi.nlm.nih.gov/pmc/articles/PMC10039256/ [11] www.reddit.com/r/chemistry/comments/15slv5/what_happens_to_potatoes_as_they_cook/ [12] aru.usc.edu/blog/did-you-know-that-by-changing-the-way-you-cook-rice-you-could-cut-the-calorie-content-of-the-rice-by-more-than-half/ [13] www.ncbi.nlm.nih.gov/pmc/articles/PMC10713747/ [14] idahopotato.com/dr-potato/potato-chemistry-in-cooking [15] santacruzparent.com/why-pasta-and-rice-may-be-healthier-as-leftovers/ [16] pubs.acs.org/doi/abs/10.1021/acs.jafc.8b06371
Great video Clive! We generally reactivate our 3A/4A molecular sieves/zeolites at 200°C under vacuum to get the most out of them. The cheap eBay ones are usually legitimate but lower grade in my experience - they're still good for dehumidification, you just need more as they have lower internal surface area. Zeolites are theoretically better per unit mass but harder to dry/activate, especially without pulling a vacuum. Silica gel, on the other hand, reactivates well at 120°C in ambient pressure.
The bentonite is prob the cheapest option as well. I've used cat litter, just thrown into each half of full size battery boxes as desiccant in my storage sheds for years. It works, even in the Pacific Northwest rainy winters, just bake it dry at the beginning of each month. I've done it for 3 years now and I've had no tools rust on me for the first effing time in my life. Nice test Clive, I appreciate you.
If you have dry fertilizer or ice melter around the house, then throwing the desiccant packets into their containers is a good way to keep them from turning into a wet, mushy mess.
I keep those that contain balls, but I toss those that contain something that looks more like cat litter since I don't want that dust in my filament box. Silica gel beads are about 10 bucks per kg, so the usefulness of saving them (especially without indicator color) is not that great.
In the Sierra game Space Quest I there is even a can of dehydrated water amongst the emergency supplies. I was very young when I first played that game and English is not my first language, so I didn't get that joke until I played it again and it made me giggle uncontrollably.
I have silica gel packets in bottom of every pocket in the veto bags and pouches. I live in a humid environment. Didn't know I had to replace them this often. Thanks Clive!
I like that the first thing you mentioned was using it to dry out/keep dry 3D filament. That's what I use desiccant for! This info was great, thank you for the work you put into this test!
Instead of watching Clive's videos, I finally finished my 3D printer that I was busy building...which brings me to filament drying, which brings me back to watching Clive's videos. The Felite-type cat litter is readily available here in South Africa, so I suspect that my custom-built filament dryer will be something akin to a cat's litterbox with a stylish lid to keep these two furballs running the household out of it. Great video, thank you Clive.🐱
Also keep in mind that if your printer has a heated bed, that can be used to dry filament. Set it in a small box (like the box it came in or 3d print one out of a heat resistant material) to trap the bed's heat
If I remember correctly, putting filament in a box with dessicant only keeps the air dry and thus prevents further uptake of moisture, but to get the moisture that's already in the filament out, some heat is required.
I used to use baked out epsom salt wrapped in paper towel as a dessicant for the optics chamber of moisture sensitive laser equipment. It worked far better than the silica gel beads in protecting the moisture sensitive crystals inside.
Hi Clive - been watching your stuff for a while. Nice analysis! I have a PhD in porous materials and work for a company that makes instruments that evaluate how well desiccants work (among others, we use a method called DVS). There are generally three important parameters that define them. First is basic - how much water they take up. Second is how fast does it take for this to happen. Third is how much energy you have to put in to activate them, meaning dry them out completely. There are some subtleties associated with each parameter, some pointed out by other commenters. The amount of water desiccants take is generally set by how much water (1) fits in pores in their structure or (2) can chemically react with the material, or both. What is interesting is that this exact amount often depends on the ambient humidity. For example, both Zeolite 13X and Silicagel can take up about 30-40% by weight of water when completely wet. The zeolite takes up the nearly the entire amount below 1% relative humidity or RH. This means that using it will keep the environment bone dry, but it will quickly be used up. Silicagel on the other hand will take up 2x more water when humidity is high (60 RH) than when it is low (30 RH). This means it is better for an environment where some water is fine, but you want to keep humidity from climbing too high. The relationship between humidity and water uptake is called a sorption isotherm. The speed at which the above happens is also important. You can have a desiccant that takes up more water than anything else … in about 6 months … so it will be worthless. We call this the kinetics of uptake. Most desiccants on the market are fairly quick to reach equilibrium, under an hour or so. Organic materials like rice tend to be slow as the water has to go inside their structure. Finally activation is important if you want to reuse the thing, and how much power you need to do it. It is governed by how strong the water interacts with the material. We measure this parameter by keeping the humidity stable and heating the sample up slowly while continuously weighing it. You can then tell how much water is lost as a function of temperature from the mass. Silicagel can be fully activated slightly above 100C, while zeolite 13X needs over 300C and a vacuum. This relationship is called a sorption isobar. Some people mentioned testing calcium chloride. It deliquesces and turns into a liquid. There is a way around this though - you can put the salt inside the pores of some other material, like inside activated carbon, so that it is confined and does not leak out when liquid. You can then get best (or sometimes worst...) of both worlds. :) If you want, I may be able to test those materials of yours. We're in the UK. Feel free to reach out!
We used Felite at one of my old jobs. We collected 3-5 gallons of water per week with it in the desert and dried the Felite every week. In the 2 years I worked there we never had to replace it.
Brings back a blast from the past. We used silica packs in telecoms cabinets. We used to put them on the tubular heaters in the telephone exchange to dry out. We reused them lots of times. Thanks very interesting.
I made a terrible mistake using calcium chloride to dry out the car after a leak. I forgot about it and went for a drive… the calcium chloride solution that had collected spilled out into the spare wheel well and fabric. It attracts water even when wet and I seemed to have an everlasting wet spot!
Yeah, that slightly gooey stuff is nasty and I suspect it even to be corrosive to metal. I used roughly about 10 bags of silica gel (each about 100 grams) in the whole car during winter pause in the garage and it kept humidity lower for about 3 - 4 months and then it was saturated. You even need a humidity logger device if you want to do it properly. And we Germans are well-known for taking it seriously.. 😉
@@DasKmbH I imagine that it absolutely is corrosive the same way other chlorides like sodium chloride would be, being deliquescent tends to keep moisture perpetually present and the resulting salt solution would accelerate corrosion the same way salt spray would. Interestingly I find that leaving those rock salt candle holders (or any chunk of rock salt) on a surface tends to lead to this thin salt crust expanding out from the base of the chunk, perhaps it's attracting moisture and the resulting solution evaporating leaving behind a thin, expanding crust of salt on the surrounding surfaces
I have a tub of anhydrous zinc chloride at work. Or should I say I used to have a tub of zinc chloride at work, I now have a tub of brown liquid as it's so hygroscopic it turns itself into a solution, even in an apparently sealed tub!
For the zeolite, it depends a lot on what type you used. This can be optimized for a variety of molecules and temperatures, or for exchanging ions. If you have a fairly standard zeolite there, like 3A or 4A, it should be able to absorb more than double of what you measured, but it is supposed to be regenerated at above 120°C. Zeolite 13x can be regenerated at 90°C and has about 23% absorption capacity by weight.
@@elitearbor I first realised how much money was in counterfeiting when I saw that 1p coins were being faked. It probably cost 0.99p to make the fake but en masse it adds up!
@@blueredbrick yes, quicklime is very effective in removing both CO2 and H2O but it is not easy to regenerate. For all practical purposes, the very low cost offsets its absorption capacity
@@janami-dharmam A small-ish glass melting oven can be found in second hand stores and even newly bought it's nothing too extreme. The only difference is that the oven includes actual de cent insulation that does not melt easily. Take a large blok of metal forging crucible orr insulating material and have a small plasma arc in a cavity, say 100 watts and it''ll keep going up in temp until the systems just breaks melt or the fuse pops. When the heat cannot escape properly it takes very little energie influx/power to keep increasing the temperature. Still I prefer silica gel beads or similary ceramic gels, less of a hassle. But sometimes you got to actually react the water or CO2 or others away to get the result you want. Similarly those 'getters' inside vacuum tube tech like crts are not perse super practical but it is needed for the proper functioning of the device for longer than a week or so. Also I'm not really liking the property of the ultra hygroscopic materials that dissolve themselves into a messy nasty mess like those calcium chloride based stuff. It's usable enough but it is my personal preference to avoid it. I've had unnecessary troubles with drying modules for drying feed gas that just turned into snot and ruined my experiments just because the person before me was apparently content with the messyness and did not bother spending a day improving that part of the system. Having your own part of a lab is awesome so can optimize it and know what to expect.
I have always known that my refrigerator is the ultimate "Desiccant" device. I had a piece of Christmas Plum Pudding in there, and I just pulled it out, and it is hard as a rock.
I think it might be necessary to consider and compare whether each material is an absorbent or and adsorbent. Maybe won't make much of a difference in deciding which is best at capturing moisture, but may make a large difference in the amount of energy to dry them back out again. Hopefully, part 2 of your experiment.... It may also be worth considering the conditions in which these materials captured the mositrue, temperature and RH, and how changes in those are reflected in the capture rate. Very interesting Big Clive (as always) 👍
Hi Clive. Very interesting, as usual. I’ve recently acquired a Bambu P1S 3D printer. It has a sealed filament holder (AMS) which houses 4 x 1kg reels. As you are probably aware the filament absorbs moisture, and this can adversely affect the quality of finished products. I’ve printed 7 containers, which hold Silica Gel, and these slot into the AMS, to control the humidity. Yesterday, as the humidity in the AMS had increased, I changed the Silica Gel, and this morning the humidity, in the AMS is 10%, whereas the humidity in the room is 65%, so it appears to be doing a good job. I put the ‘used’ Silica Gel into the microwave, on defrost, for 15 minutes to dry it out, for reuse. Your results appear to support my choice of desiccant😊. Cheers Noel.
most useful - thanks - I also save all my small silica gel packages, and I have a portion of blue indicator silica gel, that I will mix into the clear one, to se when it turns red and moist.
@@frogz Silica gel is an amorphous and porous form of silicon dioxide, consisting of an irregular tridimensional framework of alternating silicon and oxygen atoms with nanometer-scale voids and pores. It is these pores and voids which traps water/moisture but I suppose it could trap something else too.
I like the fact that the removal of water by desiccants requires no electricity but the huge amount of water that an electric de-humidifier removes from the air per day is impressive (liters). I wonder per ml of water removed what the cost difference is between the passive and active electric methods would be.
@@nightcatarts You'd get the oxidation regardless. Oxygen will always be at ~21% outside the phone, and electrolytic corrosion may very well produce still more of it on the inside. Water is a catalyst for corrosion and it provides spurious conductive paths for the battery power while simultaneously taking part in electrolysis -- which amounts to electrically-driven corrosion. No matter how it's done, the faster you can get the water out of there the better. And removing the battery, even if it involves a very difficult disassembly, is at least equally important if the device is to be salvaged.
@@nightcatarts There will be no shortage of oxygen even without moving air. Increased temperature will speed up oxidation for sure, but getting the moisture evaporated ASAP is a good move.
@@jamesg1367 I rescued my phone (fell in the toilet while doing what ones does in a toilet :) once by flushing my phone with distilled water and quickly remove the liquid by a vacuum cleaner then running to my already ready dried silica beads in a glass dessicator and a bit lowered presure etc. Was lucky to be near a lab. There was no way to remove the battery in the time it would self destruct by what you mentioned.
FYI: Zeolite is used in oxygen concentrator machines. Room air (~21% O2) goes into the column of Zeolite, and ~97% O2 comes out. (assuming it is medical grade Zeolite)
@@penguin44ca PURE water boils at 100 C. But zeolites with water absorbed is not pure water. If you would like a simple example, make a 50-50 mix of sugar and water, and see when it starts to boil.
EPSOM SALT! Try that, though you need to find a way of containing it as it will expand when it absorbs moisture. To make it anhydrous, simply heat it to about 80 degrees for about 10 minutes, and stir it before ramping up the temperature to 110 degrees C - and leaving it for another 10 minutes, stirring occasionally. I did this in a glass jar in an oven - so the end result may vary; but the idea behind stirring is to stop it from forming a solid hollow 'cake' which is really hard to get out, and may not have as much surface area as the granular powder you get when you stir it up as it dries and shrinks... Also you don't want to melt it... The result is a *very* active desiccant, such that it shrinks down to about 1/4 the original size when dried, and is difficult to keep 'purely anhydrous' since it will immediately draw moisture from the air once the temperature drops below 80 degrees!
Properly dried zeolite is most effective for critical drying of process gases. On the other hand, zeolites (there's a whole range of these) can be used to remove pollutants from water by dint of being 'molecular sieves'
I wouldn't have guessed you could effectively dry desiccants in an air fryer. But I'll mention I got this rack accessory thing included with a new heat pump clothes dryer which lets you dry shoes and such in it without it tumbling around. I tried putting 1 kg of silica gel in it one day and it worked amazingly well, both in terms of quickness, ease and power consumption, now my go to method. Kinda makes sense to me though, an oven is just a hot, sealed enclosure, surely the air just saturates pretty quickly? Whereas a dryer actually removes the moist air. It's also a lot cooler around 60 °C so (most) plastic desiccant holders don't melt (eg. PLA will deform).
Ovens are not a sealed environment. They have a small vent that typically vents through the back of the range near the dials, or through a rear coil top depending on model. Steam and hot air escapes through this and fresh air is drawn in.
That makes a lot of sense, but is 60C hot enough to dry it out in a single drier cycle? Clive was suggesting even 90C from the little heater unit he used might not have been enough, and while there's an additional boost from using a heat pump drier which directly dehumidifies the air as it cycles that still might not be enough to fully dry the desiccant out
@@JourneysADRIFT Because you said "range" I assume you're from North America where gas burner ovens are common (they're now banned here in Australia for air quality and fire hazard reasons). My understanding is almost all gas ranges vent the oven space because they have to burn a fuel inside, but in most countries electric is vastly more common, those don't vent the oven space apart from for pressure equalization. Almost all modern ones do have fans and vents on them but that's just to cool the electronics and the outside of the oven in the cabinet and sometimes the front glass. If you do try to dry water logged things in an electric oven you'll find you have to open the oven door every so often and when you do the built up steam is often visible to the eye.
@@WizardTim Range doesn't mean gas specifically, just the oven/cooktop combo. It can be any flavor. My electric one does have a vent in the rear that is for steam/vapor to escape.
@@Tinker001 Cat urine is in fact exceptionally corrosive, which is something i know from laptop repair. Because they love sleeping on a warm keyboard and leaking a couple droplets occasionally. Also prefer not to have the smell when repairing things.
@@SianaGearz I've had a keyboard sacrificed to cat drool (she would curl up next to it when I was working--took out F1), but I am very glad I've never had to cope with the smell of hot cat piss.
Great, comprehensive test. I use silica cat litter in my outdoor electrical boxes to fight moisture and in sewage treatment plants, moisure comes with agressive sulphites or sulphates that spoil copper wires and contacts. Cat litter for me justifies its price many times over. Silica gel ir rare and expensive. Will check out bentonite litter if i find it in local shops.
The bentonite/felight comparison is very well taken. A final comparison column that would be very useful is cost - how many ml of water absorbed per penny of first cost. I would expect the rice to be the cheapest, but it presumably can't be re-used as many times as the mineral products. You put ez-cook rice in salt shakers, partly for its dessicant effect, to protect the salt from clumping, but also partly because the large grains help to avoid flow problems.
I liked this video, very educational, I don't have the patients to test like this, but I would like to see two additional things carried on from this video: 1 - Drying the materials past the 90'C limit, the air fryer is ideal for this as it has high heat and decent air circulation, 160'C is what I use for my colour changing desiccant that I sit in a old metal pie tin, with drying time taking between 10-25mins depending on how much I'm drying. 2 - I'm curious about where in the chart those cupboard style desiccants that come in a plastic tub that you peal the silver foil off. I use these in my car. 3 - How about salt? Baking soda? Laundry powder:? That stuff oes like rock 30seconds after you open the box.
Good video. Although drying them out at a higher temperature may show their maximum potential, I believe your results are still accurate. Not only was it a consistent drying procedure, it's much more realistic to what the average power-user would be doing. I mean, sure, we could all dry them out in a used toaster oven, but when you already have those desiccant dryers, I think most of us are likely to take the easier route and use the dedicated dryer that we can leave on for the day. I think it would be interesting to see their maximum potential, for science, but these results are much more relevant to the common power-user.
Another desiccant is calcium chloride, aka with the corporate name in the US of "Damp Rid". It actually liquifies it absorbs so much moisture. Reusable too. BTW, did you notice the cool electrostatic effect the plastic bag had on those zeolite prills? First time I ever saw that effect was with those tiny (carbon?) prills/balls that you can find inside many old hard drives. I think they also were used for desiccation. This was an interesting video Clive. Thanks.
Interesting. I bought some "Moisture Traps" from Poundland in the UK and the one I put in a 3D printer enclosure is now totally liquid (old damp house in Wales!). The instructions tell you to dispose of it. I've just noticed it contains calcium chloride, so does that mean I can convert this disposable product into a re-usable one?
@@EcoHamletsUK Yes, the calcium chloride solution can be evaporated in the microwave or on a tray in a low heated oven. Scrape up the dry flakes and start again.
Another material is the stuff they make disposable diapers (nappies) with. Amazing absorption, though I don't know how good they'd be for drying things out.
Aluminum Oxide is a well-known desiccant. I bought 10 pounds a couple of years ago. I use Mason Jars with mesh lids and swap them monthly to keep my filament container dry. I dry the old desiccant in the Mason Jars in an oven and then use a regular lid.
This video was really informative. It would be great too see the difference if they were dried really well first. I'm also curious what the rate of absorbtion would look like withen the first few days, or even hours. This could be useful for drying objects.
Great results, i expected the zeolite to do better. How about anhydrous magnesium sulfate, calcium chloride, etc.? From what I understand it'll take a lot more energy to "recharge" but may absorb much more humidity...
Hi Clive, Zeolite binds water quite tightly (up to 30%) in its structure so in order to 'dislodge' it out again, you really want to go a bit higher than 90°C. In our lab, we used to bake the zeolite at 120°C. I think, industrially, they go even higher to get really 'activated' zeolites. It's quite important to check which zeolite you have; usually it's the 4A stuff. A good test for zeolite dessicant; take 10-20 grains of (cool, dried) zeolite in your hand and put a few drops of water on it. You should feel them heat up noticeably. If you don't feel that, your zeolite is maybe the wrong type or degraded;
Try the super fine silica used in water pillow type humidifiers. Also try putting the whole apparatus in a sealed container ported with one of your solid state dehumidifiers. Check to see if you can increase the saturation, and also see if voltage is generated due to the humidity gradient across the membrane of the solid state dehumidifier element.
I work in a lab with ultra-high vacuum chambers (made of steel), and to achieve ultra-high vacuum you have to bake (=outgas/degas) the chamber at 200°C for two weeks, which is the temperature and time most people agree on. I think this is because there is another desorption peak of water at about 180°C, the main peak being at about 100°C (for obvious reasons). Being a thermal-activated process (as you might guess), it is logarithmic. That means you can do bake-outs at 60°C or even at room temperature when pumping, but it will take months or years instead of days at 200°C to achieve the same results. I am not saying that you got this all wrong because your results are interesting, but I clearly would recommend you drying the stuff at more than 120°C in a kitchen oven instead.
The DampRid products in the US use calcium chloride. Also, I live on a dirt road. Twice a year the state sprays this in front of my house to keep the dust down. It's greatly appreciated since the road is on a steep mountain, and some like to spin their tires to make clouds of dust.
Very good! I have a personal interest in this (you do that a lot with your vids - Ms.Flambeaux excluded :D)... I have a hyper-baric compressor that can easily go to 4000lbsin2 (i.e. ~300 bar) and the target for the compressed air really does need as close to zero moisture as possible to avoid damage. There is a two stage piston in the cylinder with a first stage "basic" compression, and then a second stage "final" compression that has a tiny "needle" piston with massive cyclinder walls. The problem comes in with moisture in the air at these pressures and dimensions and it gets really hot when working hard - 100C+ easy. I run the input through a series of cotton "swabs" that take out any obvious moisture and there is a gravity-fed bleed valve that needs opening several times during a session and always produces hot emulsified oil & water. The final output is then fed through more swabs (to remove oil vapour mainly) and then into a thick-walled cylinder which is the final drying chamber. Inside is an acrylic tube about a foot long filled with colour-changing silica - it starts out orange and changes to dark green when it has absorbed moisture. The tube is a loose friction fit so as not to burst it in the high-pressure air (i.e. pressure is the same both sides of the wall) with an O-ring at the far end so the air can't sneak past but rather has to pass over the silica. The output air should be very dry but I wonder how quickly the silica will absorb moisture? That said, the silica is still orange and I would have thought if my pre-drying was shabby, I would at least have seen some disclouration (it does in normal air). I have seen "Molecular seive" available for drying but I don't know what the material actually is for reference. From your figures, the 337g of silica you started with seems a bit more than in my acrylic tube-ful (never weighed it but will now) and rough maths says it was taking out ~25ml per week, which, say, is ~4ml per day or 160ul per hour... which now I write it doesn't sound too bad. I wonder if the forced airflow and huge pressure will make any difference in my case. The pessimist in me is mindful that high pressure tends to squish the water tighter into the air molecules (hence high pressure = fine weather) so maybe the final drier is not as effective as it might if it were pre-drying - i.e. on the air intake somewhere. Unfortunately I have no way of measuring. So my concern is not so much "quantity" but rather "how quickly"... I am going to start with dried silica (yes you can re-use it) and do before and after measurements. I have to spend some time thinking about what constitutes a good test... time or volume of air - this latter is considerably and I would need several goes at it just to let the compressor cool down. Thanks Clive... inspired me to do some tests of my own. Maybe even video it and post it. Cheers h
How dry do you want it to be ? Sometimes I'd use quicklime pellets/rocks in a closed glass desiccator with or without vacuum. Depends on what you try to dry. Once I had to dry ammoniumacetate to form nice dry pure crystals, well that needs a closed system with the quicklime but no heat or vacuum otherwise it will either melt or sublime. Water vapour and also the carbondioxide that is present in the air reacts with the lime to form the hydroxide and carbonate from the air. The quicklime can be regenerated by calcinating it in an high temp oven such as uses for glass working. And yeah please use both the mass and volume for comparing different methods of drying agents. A wet phone would brake if under full vacuum but nested in silica drying beads in a glass desiccator and a bit lowered pressure and an infrared lamp pointed at the setup to ,say, 40 degrees C does wonders. Also its important to know which type of "wet" is the culprit. Rainwater is ok enough to put it directly into the system. But spilled beer or soda or even tap water is nasty. Then asap spray and rinse with distilled water quicly to get rid of salts and use a vacuum cleaner (with care other wise the speakers etc will pop ) for example to remove the bulk of the liquid. Then to dessicator and hope for the best. An alcohol solvent the 100% pure type either methanol ethanol or IPA can also be usefull for cleaning and drying but in the case of a phone I bet it would damage it. It is upsetting that batteries are no longer easily removable from devices nowedays, it would prevent a lot of damage if you could can remove the battery in a hurry and then also do the rinsing and drying ritual.
Nice, interesting, good methodology! Thank you! 😃👍 - rice: THE standard desiccant for salt in East German restaurants near lakes or the coast - silica: I expected it to be the best, there must be a reason why everyone uses it. If you have leftover silica bags from your purchases in leather or electronics: throw them into a drawer where your jewels or your silverware is. It's the best in avoiding blackening of jewels and silverware!!! - bentonite: Used for the clarification of non-vegan wine and apple-juice - bentonit is mixed into the beverages for catching impurities, egg yolk is mixed in and lets the impurities with the bentonite fall out and settle in flakes. Is it used as an oil catcher in filling (gas) stations? I'm not sure. - zeolite: An ingredient of detergent powder for laundry. - What did the USA use as desiccant for army and astronaut's food? Little permeable bags with iron powder - it absorbs water and oxygen independently and transforms it into rust.
Thanks for doing this Clive. I have a couple of questions: Were these tests run at the same time (so that the RH was the same for each test)? Do there media perform the same repeatedly (i.e. after re-drying and re-using)? I'm sure a higher drying temp would give better dehumidifying results but this is fine for real-world use. I appreciate your work, cheers.
You know we're very keen to see the Excel graphs, BC! Although obviously non-reuseable, Calcium Chloride granules are a widely - available, VERY good "domestic spec." desiccant. Phosphorous pentoxide is amazingly good (but reasonably hazardous - phosphoric acid isn't nice stuff!)
Back in my caravanning days, I used trays of calcium chloride crystals to keep the moisture at bay. In a week or two they would have completely disappeared, leaving behind a tray full of (not) water. They were only a pound or so from Home Bargains or B&M.
While I scoff at the whole 'submarine phone' dried in rice, I ALSO scoff at the 'warm dry place'. Personally, I throw the ENTIRE phone into something like anhydrous methylated spirits (which is basically denatured ethanol) and give it a real good 'swim' in the stuff. Any water will RAPIDLY mix with the ethanol thereby DRAMATICALLY 'diluting' the amount of water left in contact with the electronics. Once removed from its _BATH_ in solvent, then get your wife / girlfriend etc hair dryer and put it on fan only (i.e. no heat) and throw the phone in the airstream to rapidly evaporate any remnant alcohol. A BONUS is that this will give it a half decent clean at the same time and the half-arsed flux cleaning that was done at the factory is improved upon!. A potential DOWNSIDE is that SOME plastics don't overly like ethanol (but such plastics don't get used on phones, so you should be fine). I know it SOUNDS counter intuitive to DRY something by first fully immersing it into a (wet?) liquid, but I can guarantee you that within a few minutes, it will be SIGNIFICANTLY dryer than if you'd placed that phone in a bed of rice!!! NB: If the initial 'swim' the phone took was in sea water (i.e. SALTY), then it's best to first drown it in distilled water a few times to rinse out as much salt as possible. (Once again, this SOUNDS counter intuitive). Pure (distilled) water does not conduct like salty (impure) water does. It's all those impurities that will destroy your phone rather than the water itself. As the water component evaporates, it effectively CONCENTRATES the remaining (salty) impurities!
Two notes of context for others reading this: 1) Conformal coat can be removed by some solvents, and so tin wisker susceptibility or weatherproofing can be affect. Ask me how I know… 2) Salts are generally insoluble in ethanol, isopropyl, etc.. This is why you use distilled water first.
@@tylervanderkley I agree that conformal coating is often easily dissolved by many (most?) carbohydrate solvents, I've not seen any mobile phones that actually use conformal coatings. (But that does NOT mean such devices don't exist!). The conformal coating I use is handy in that it doesn't need to be removed if any 'rework' is required on the board. (Just apply another coat once it's repaired) NB: Some people aren't aware of the difference between solder mask and conformal coating. Solder mask (often green in colour, but available in almost every colour these days) is applied to the bare board BEFORE any components are added. One of its many purposes is to avoid solder bridges. There are intentional GAPS in the solder mask to expose the pads that the components are soldered to. Conformal coating is (generally) applied AFTER all the components have been soldered to the board. It's purpose is to seal the ENTIRE board (including the component pins that have just been soldered) from exposure to the elements (such as humidity etc). My last quasi-humorous comment explains all I was 'taught' by a wise old man about waterproofing electronics that have to live outdoors... 1: Spend an inordinate amount of time coating everything and sealing it up nice and tight into a suitable enclosure. 2: Once that has been accomplished, bore a fairly decent sized hole in the bottom of your newly sealed enclosure so that all the water that WILL get in has somewhere to drain out of! YES, it sounds ridiculous, but whenever I follow that process fully, the thing lasts. And when I don't precisely follow that process, it will only last a few months at most!
There are a LOT of different types of zeolites, but for the common ones intended to adsorb water, you really need to dry them between 200-220°C at least. (Some kinds of molecular sieves even require overnight drying under vacuum at 300°C, immediately before use!) Also keep in mind that "drying" doesn't just mean "sucking up" liquid water or absorbing water from the air at high relative humidity. Unless the drying agent chemically reacts to destroy the water, there will always be some amount of free water left over, because the water adsorption/desorption processes will eventually reach a dynamic equilibrium. This is why adding multiple times the mass of dessicant, that you theoretically need to adsorb/absorb all of the water in a fixed volume, results in not only faster drying but also gives you a dryer end product. For example, a good zeolite will adsorb water from fluids even at relatively high temperatures (50-80°C) and will be able to maintain single digit PPM levels of water contamination at equilibrium (assuming a large enough excess is used). At the other extreme, rice will actively make a truly dry fluid *much* wetter (going from ~10 PPM of water to > 1,000 PPM), even if you dried the rice at higher temperatures and used it immediately after. Some Zeolites just "bind" the water much stronger than any other reusable dessicant (hence the high temperatures needed to dry them) and they can therefore effectively dry a larger variety of materials (i.e. you could use 3A molecular sieves to dry rice or bentonite clay, but you can't do the reverse. This is important when the thing you're drying is itself hygroscopic.)
How much energy does it take to reconstitute the dessicants? Could one of them be cheaper than the rest to reconstitute? For indoor spaces, I'm thinking the most cost-effective means to dehumidify might be heat recovery ventillation but I suppose it depends on local climate.
Would it be possible to test Sodium polyacrylate as well? You might have to use less since it can really expand but it might be an option to look at as well! Keep up the awesome vids!
Silica Gel in much larger quantities is used to stabilize humidity in an area over time. Say you had a museum of textiles and you want to keep the humidity at a certain point. The silica in many kilogram quantities is used to manage swings in humidity in the various display and off display area.
Good test. I will say hot air absorbs more moisture than cool air. So in an ideal situation, you would heat the entire room to adsorb all moisture from the room into the air and then push it through the drying media. But your little heater probably helped a bit, Im just curious about the rest of the room. I.e. a humidity measurement from the room would be an interesting thing to follow. But it would probably have to be a relatively small room to see any real changes. Good job. I love it.
Never in a million years would I have thought I'd be watching a Big Clive video about desiccant. I need reusable desiccant for my 3d printer filament storage tote. After seeing this video and seeing how well silica did, I might just get some silica. I'll probably spring for the orange color changing silica (get the orange because its non-toxic as opposed to the blue which has cobalt).
Activated alumina works much better. It keeps pulling moisture out of air to much lower levels than silica gel can. I believe silica gel works faster, until it just stops pulling moisture.
Activated Alumina is a very reusable desiccant, I personally don't care about the reusable aspect so I have been using Calcium Chloride. It can be bought for as little as 3 usd per pound or 450 grams so its very cheap and its cheaper to buy more than to dehydrate it although it is technically possible. Plus it turns into hard water when its fully used up, so its very noticeable when it's all used up. It keeps my nylon filaments extremely dry.
Interesting, volume versus weight. Does the container stop the dessicant from absorbing moisture as by volume the dessicant can not expand as it is full to the brim? Do they also then have the reverse effect, if they are saturated and not replaced will they then release moisture back into the air? Interesting subject and experiment.
Activated Alumina and magnesium sulphates would be nice additions. You can get magnesium sulphate monohydrate (MgSO4•H2O) by heating Epsom salt to 120°C and anhydrous magnesium sulphate by heating to 250°C. Epsom salt is magnesium sulphate heptahydrate (MgSO4•7H2O)
Ramp the heating slowly and give it time to soak. I chucked a pan in a hot oven and it melted down first and ended up being a solid mass when I was done. The slow ramping allows for the moisture to drive off vs puddling out and left me with a fine dry powder.
Good info! Thinking of cutting all the silica gel packets I have here, drying them somehow, and leaving on the car that is parked underground... as I don't drive much, sometimes I get some fungus when I go give it the routine run around.
The reason to put a damp item in a descant is not to absorb the moisture directly but to render the air around the item dryer to evaporate and capture more moisture from the item. A deep baking pan with (clean) kitty litter in the oven for an hour and when it cooled enough you put the item on top with a air gap and the pan in a air tight container/bag to give the item a elevated chans of drying out. I would how ever suggest that immersing the wetted item in pure ethanol/alcohol would "rinse" the water out by dilution and shorten the drying time as alcohol evaporates faster than water, and may clean water residue from the item. You could then use the desiccant to speed up the drying further. If it will save a phone dropped in the water or not will largely depend on if the water shorted out and burned any part of it. A phone with no battery put in clean water has a high chans of recovery as does most un powered electronics, I once carried a crt monitor home in pouring rain with no box and after removing the cover and putting it in front of a fan over night it worked just fine. Salt water is a different story, chans of recovery is slim to none.
Clive, what I would love to see is how good they are at retention of water, for example, I have been told that Carbon Fibre 3D printer filament will actually pull moisture out of silica gel whereas it wouldn't from Zeolite so for drying purposes, silica gel wouldn't advisable in this scenario unless the silica it was perfectly dry to begin with
Big Clive - Probably the only human to ever have an air fryer dedicated to cooking kitty litter, and I respect that.
Yes you sometimes never know the worth of a man until he frys some kitty litter.
For cryogenics we use zeolite for drying our process gases. There are different types of zeolite. Our canisters contain silica gel beads for color indication of saturation. The zeolite is such a strong desiccant that it will pull moisture out of the silica gel. Now it might be that by weight silica gel is better, but it's my understanding that zeolite is capable of drying out a gas to a much greater degree. It's also possible you got counterfeit zeolite or an unsuitable grade of zeolite. Also, we regenerate our zeolite using heat and a vacuum pump in concert to get it extremely dry.
Zeolite will continue pulling moisture at MUCH lower humidity levels. Silica gel can hold more total, but it equalizes with ambient humidity at a much higher humidity level. Zeolite will keep pulling until there's nothing left, or the zeolite is saturated.
Absolutely. Zeolite works in a pressure swing drier.
We used it for an infrared camera that was cooled to cryo temperatures. The slightest moisture would have ruined it, but the pressure swing zeolite produced absolutely dry air.
@@russoft Probably fake sieves
@@JohnDoe-fk6id thank you for articulating that better than I did
Well, that explains why my lot didn't work- thank you for your comment!
“I do have an air fryer now dedicated to drying desiccants…”
There is no more “Big Clive” sentence than that!
Wonderful.
Two months' work; eight minutes of video. That's dedication!
You misspelled "desiccation" there.
Having a dedicated air fryer for drying desiccant is peak Big Clive energy
@@TheRealBobHickman It is also very smart, because the color changing silica gel is actually toxic.
@@dl200010 the blue ones ? Yeah those contain a bit copper. Dont eat it.
@@blueredbrick The blue ones don't contain copper. They contain cobalt chloride. The orange ones contain methyl violet. Both are much more toxic than copper. But yes, don't eat them, but also know they do leave residue of the color changing material on whatever they touch, especially when heated.
@@dl200010 oh cobal? Interresting . My mistake. Never knew it was cobalt based. I mistakingly assumed (or though so reading about it long ago) t must have been copper.
Ps, I find it an interesting topic so I went into the rabbit hole of looking up the different versions and history etc. It appears that in the EU cobalt indicator is no longer allowed for kitty litter, and a methyl blue due is used and the in version I only ever saw are the packages with mostly clear amorphous kistals/chunks with on a few blue with a hint of green colored ones, but after looking at the different products offered I learned that all blue packages silica kitty litter is also being sold but never saw that here. But no copper based dyes in any case or nickel for that matte.tnx for pointing that out. Learnt a few things. My cats do not like it so never noticed the silica with added methyl dye leaving staines. that is a typical nuisance voiced by reviewers of brands sold here. I do not expect the cobalt versions to leach out of the silica matrix. good news overall. Found some loopholes to get the cobalt versions (that I no longer approver of btw even when it is
nice to look at). I also found a brand here that leaves out any form of wet indicator and is pure amporhous silica. That also is good news; cheap acces to a good drying material without impurities.
@@dl200010 It appears that the cobalt version is no longer being sold in the EU here, went on a google search and its interesting. Tnx for pointing this out. We have both pure clear silica litter and clear and a few blue colored ones in the mix based on a version of a.methyl blue due like youwntioned. Never saw the orange ones but did not go looking those tbh in the stores. I'm happy to have found a brand that leaves out any fragrant or indicator dyed beads. Cheers.
I think the advantage of zeolite/molecular sieves is not how much it holds, but how aggressively it can pull water out of low humidity air or solvents. Calcium chloride would've been an interesting candidate too.
Molecular sieves also stay more effective at high temperatures than most other dessicants if memory serves.
If my younger self witnessed me right now getting such a thrill from this video title.....
10 years ago i woulda thought to my self: why would i watch this?
Annnnd here we are... thrilled to watch this. =)
Omnia mutantur, nos et mutamur in illis.
I sent a screen shot to my mate who is on vacation in Prague. No response
Don’t quote me on this (he says while typing on the internet) but I recall reading that cooking rice, or any starch really, crosslinks the sugars and starches making them absorb less water than raw, hulled rice.
Also, different desiccants must be heated to different temperatures to drive off the most water. Just taking them to the in-air boiling point of bulk water can’t push out the intercalated water from clay grains.
Also also, doing that fundamentally changes the structure of most kinds of clay from the hydrated forms. Therefore their densities and water absorption properties can change quite a bit depending on the drying temperature.
It’s been a long time since I had anything to do with desiccants, so your mileage may vary.
I wonder where that cross linking action would come from, in my mind which is definitely not to be quoted i would have expected the opposite, cleaving action.
you are right; for best results, use P2O5 but that cannot be regenerated so easily. Same is true for H2SO4
Getting water past it's phase change temperature will release it from any material not chemically bonded to it. It's only a matter of time.
To properly dry out bentonite clay, a temperature range of **150°C to 200°C** (302°F to 392°F) is recommended. This range is effective for removing moisture without damaging the clay's molecular structure or properties[1][2]. Drying bentonite at higher temperatures, such as those above 500°C (932°F), can irreversibly remove crystallization water and degrade the clay, turning it into a non-functional aggregate[2].
For industrial purposes, rotary drum dryers are often used to achieve the necessary moisture reduction, typically bringing the moisture content down to between 5% and 12%[2]. It is crucial to control the drying process carefully to maintain the quality and functionality of the bentonite clay.
Citations:
[1] www.sciencedirect.com/science/article/abs/pii/S0169131717304222
[2] www.ftmmachinery.com/blog/bentonite-processing-process-and-equipment.html
[3] kegriver.com/the-importance-of-moisture-content-in-bentonite-sulfur-clay/
[4] library.csbe-scgab.ca/docs/journal/30/30_2_237_ocr.pdf
[5] temaprocess.com/2020/drying-bentonite-clay-using-tema-process-fluid-bed-dryer/
[6] www.wyomingsunmade.com/sun-drying_23.html
[7] www.medicalnewstoday.com/articles/325241
[8] digitalfire.com/material/bentonite
[9] skyorganics.com/blogs/blog/5-ways-to-use-indian-healing-clay-bentonite-clay
[10] www.mnclay.com/AddToCart2.aspx?ProductGroup=BENT
[11] www.reddit.com/r/HaircareScience/comments/fuc42n/how_using_bentonite_clay_has_saved_my_fine_oily/
[12] www.douyee.com/en/products/item/566/clay-desiccants
[13] homedistiller.org/forum/viewtopic.php?t=68673
[14] www.happyherbalist.com/bentonite-clay-8-oz/
[15] blog.biokeram.com/bentonite-in-my-formula-how-to-dry-faster
[16] www.silica-gel.it/en/content/12-activated-clay
"but I recall reading that cooking rice, or any starch really, crosslinks the sugars and starches making them absorb less water than raw, hulled rice."
There is no sugar in rice. Cooking converts rice to gelled form. One type of rice, called boiled rice (or parboiled rice) has been cooked and then dried. Puffed rice is the preferred desiccant.
"Just taking them to the in-air boiling point of bulk water can’t push out the intercalated water "
right; zeolites are clay with pores. If you soak the beads in water (saturate it) and then remove the external water by heating around 100C, you will get an idea of bound water. Most of the zeolites are lab made these days (bentonite is natural)
@@janami-dharmam Starches are just complex sugars. Repeated cooking of starches does change their chemical properties:
## How Re-Cooking Changes the Structure of Starches in Potatoes and Rice
The process of cooking, cooling, and reheating starchy foods like potatoes and rice significantly alters the structure of their starches. This transformation primarily involves two key processes: **gelatinization** and **retrogradation**.
### **Gelatinization**
When starchy foods such as potatoes and rice are cooked, the heat causes the starch granules to absorb water and swell. This process, known as gelatinization, disrupts the crystalline structure of the starch molecules, primarily amylose and amylopectin, making them more digestible. During gelatinization:
- The starch granules absorb water and swell.
- The crystalline structure of the starch breaks down.
- The starch becomes more accessible to digestive enzymes in the small intestine, converting it into glucose more readily[2][5].
### **Retrogradation**
After the cooked starches are cooled, a process called retrogradation occurs. During retrogradation:
- The amylose and amylopectin chains realign and form a new crystalline structure.
- This new structure is more resistant to digestion, hence the term *resistant starch*.
- Resistant starches pass through the small intestine undigested and reach the colon, where they act as prebiotics, feeding beneficial gut bacteria[1][3][6].
### **Reheating**
Reheating these cooled starches can partially disrupt the crystalline structure formed during retrogradation. However, not all resistant starch is broken down:
- Reheating can decrease the amount of resistant starch slightly, but a significant portion remains intact.
- The reheated starches still exhibit lower digestibility compared to freshly cooked starches, leading to a reduced glycemic response[1][2][9].
### **Health Benefits**
The formation of resistant starch through this cooking-cooling-reheating cycle offers several health benefits:
- **Improved Glycemic Control**: Resistant starch does not raise blood glucose levels as much as digestible starch, which helps in managing blood sugar levels[1][6].
- **Enhanced Gut Health**: Resistant starch acts as a prebiotic, promoting the growth of beneficial gut bacteria and producing short-chain fatty acids like butyrate, which are beneficial for colon health[2][3].
- **Increased Satiety**: Foods high in resistant starch can increase feelings of fullness, which may aid in weight management[3].
### Practical Applications
To increase the resistant starch content in your diet:
- Cook starchy foods like potatoes, rice, and pasta.
- Cool them in the refrigerator for at least 12-24 hours.
- Reheat them before consumption if desired. Reheating does not significantly reduce the resistant starch content[1][3][9].
In summary, the re-cooking of starches in foods like potatoes and rice involves the processes of gelatinization and retrogradation, which alter the structure of starch molecules, making them more resistant to digestion and offering various health benefits.
Citations:
[1] www.healthline.com/nutrition/cooling-resistant-starch
[2] www.bernard-preston.com/Reheating-resistant-starch.html
[3] hopkinsdiabetesinfo.org/what-is-resistant-starch/
[4] www.sciencedirect.com/science/article/abs/pii/S0268005X20329179
[5] chemistry.stackexchange.com/questions/116895/does-cooling-a-potato-change-the-nature-of-its-carbohydrates
[6] pubmed.ncbi.nlm.nih.gov/26693746/
[7] www.sciencedirect.com/science/article/pii/S0023643895945520
[8] www.ncbi.nlm.nih.gov/pmc/articles/PMC7984060/
[9] www.nytimes.com/2023/11/08/well/eat/resistant-starch-pasta-rice-leftovers.html
[10] www.ncbi.nlm.nih.gov/pmc/articles/PMC10039256/
[11] www.reddit.com/r/chemistry/comments/15slv5/what_happens_to_potatoes_as_they_cook/
[12] aru.usc.edu/blog/did-you-know-that-by-changing-the-way-you-cook-rice-you-could-cut-the-calorie-content-of-the-rice-by-more-than-half/
[13] www.ncbi.nlm.nih.gov/pmc/articles/PMC10713747/
[14] idahopotato.com/dr-potato/potato-chemistry-in-cooking
[15] santacruzparent.com/why-pasta-and-rice-may-be-healthier-as-leftovers/
[16] pubs.acs.org/doi/abs/10.1021/acs.jafc.8b06371
Great video Clive! We generally reactivate our 3A/4A molecular sieves/zeolites at 200°C under vacuum to get the most out of them. The cheap eBay ones are usually legitimate but lower grade in my experience - they're still good for dehumidification, you just need more as they have lower internal surface area. Zeolites are theoretically better per unit mass but harder to dry/activate, especially without pulling a vacuum. Silica gel, on the other hand, reactivates well at 120°C in ambient pressure.
Well documented! Would have been perfect if 2 more columns were added: i) ml absorbed per cm3 of desiccant ii) cost of desiccant per ml absorbed
The bentonite is prob the cheapest option as well. I've used cat litter, just thrown into each half of full size battery boxes as desiccant in my storage sheds for years. It works, even in the Pacific Northwest rainy winters, just bake it dry at the beginning of each month. I've done it for 3 years now and I've had no tools rust on me for the first effing time in my life.
Nice test Clive, I appreciate you.
Awesome to know those silica gel packs are very worth saving and reusing. Thank you so much for this information!
Saved them since always 😊 I have a big bag now
I save them for synthesizing sodium metasilicate. Now I can save them for two reasons!
If you have dry fertilizer or ice melter around the house, then throwing the desiccant packets into their containers is a good way to keep them from turning into a wet, mushy mess.
I keep those that contain balls, but I toss those that contain something that looks more like cat litter since I don't want that dust in my filament box. Silica gel beads are about 10 bucks per kg, so the usefulness of saving them (especially without indicator color) is not that great.
If you own an enclosed 3D printer with heated bed you can use that to dry filaments and desiccants though not recommend at the same time
I'll keep the "dry humour" to a minimum. 😉 Great video!
Hahahahahaha
My favourite is dessicated coconut
-head explodes-
In the Sierra game Space Quest I there is even a can of dehydrated water amongst the emergency supplies. I was very young when I first played that game and English is not my first language, so I didn't get that joke until I played it again and it made me giggle uncontrollably.
I have silica gel packets in bottom of every pocket in the veto bags and pouches. I live in a humid environment. Didn't know I had to replace them this often. Thanks Clive!
remember, you don't have to replace them, you can simply bake them for awhile and then reuse them. They'll last basically forever.
Good to see Big Clive back up and running
"Back up and running?" ... Has he been away? I've not noticed? Was he banned again by IdioTube?
Seems like he’s just spent 3 months weighing cat litter…
How was this comment made 3 weeks ago?!
@@marcse7endid you notice that the comment was made 3 weeks ago? How?!
@@brabhamfreaman166 As you do 😸
I like that the first thing you mentioned was using it to dry out/keep dry 3D filament. That's what I use desiccant for! This info was great, thank you for the work you put into this test!
Instead of watching Clive's videos, I finally finished my 3D printer that I was busy building...which brings me to filament drying, which brings me back to watching Clive's videos. The Felite-type cat litter is readily available here in South Africa, so I suspect that my custom-built filament dryer will be something akin to a cat's litterbox with a stylish lid to keep these two furballs running the household out of it.
Great video, thank you Clive.🐱
Also keep in mind that if your printer has a heated bed, that can be used to dry filament. Set it in a small box (like the box it came in or 3d print one out of a heat resistant material) to trap the bed's heat
@@KP-ty9yl Thanks for the info!
If I remember correctly, putting filament in a box with dessicant only keeps the air dry and thus prevents further uptake of moisture, but to get the moisture that's already in the filament out, some heat is required.
I have no idea why I clicked on this video so quickly. But, by hell, am I glad I did.
I used to use baked out epsom salt wrapped in paper towel as a dessicant for the optics chamber of moisture sensitive laser equipment. It worked far better than the silica gel beads in protecting the moisture sensitive crystals inside.
Hi Clive - been watching your stuff for a while. Nice analysis! I have a PhD in porous materials and work for a company that makes instruments that evaluate how well desiccants work (among others, we use a method called DVS).
There are generally three important parameters that define them. First is basic - how much water they take up. Second is how fast does it take for this to happen. Third is how much energy you have to put in to activate them, meaning dry them out completely. There are some subtleties associated with each parameter, some pointed out by other commenters.
The amount of water desiccants take is generally set by how much water (1) fits in pores in their structure or (2) can chemically react with the material, or both. What is interesting is that this exact amount often depends on the ambient humidity. For example, both Zeolite 13X and Silicagel can take up about 30-40% by weight of water when completely wet. The zeolite takes up the nearly the entire amount below 1% relative humidity or RH. This means that using it will keep the environment bone dry, but it will quickly be used up. Silicagel on the other hand will take up 2x more water when humidity is high (60 RH) than when it is low (30 RH). This means it is better for an environment where some water is fine, but you want to keep humidity from climbing too high. The relationship between humidity and water uptake is called a sorption isotherm.
The speed at which the above happens is also important. You can have a desiccant that takes up more water than anything else … in about 6 months … so it will be worthless. We call this the kinetics of uptake. Most desiccants on the market are fairly quick to reach equilibrium, under an hour or so. Organic materials like rice tend to be slow as the water has to go inside their structure.
Finally activation is important if you want to reuse the thing, and how much power you need to do it. It is governed by how strong the water interacts with the material. We measure this parameter by keeping the humidity stable and heating the sample up slowly while continuously weighing it. You can then tell how much water is lost as a function of temperature from the mass. Silicagel can be fully activated slightly above 100C, while zeolite 13X needs over 300C and a vacuum. This relationship is called a sorption isobar.
Some people mentioned testing calcium chloride. It deliquesces and turns into a liquid. There is a way around this though - you can put the salt inside the pores of some other material, like inside activated carbon, so that it is confined and does not leak out when liquid. You can then get best (or sometimes worst...) of both worlds. :)
If you want, I may be able to test those materials of yours. We're in the UK. Feel free to reach out!
We used Felite at one of my old jobs. We collected 3-5 gallons of water per week with it in the desert and dried the Felite every week. In the 2 years I worked there we never had to replace it.
Brings back a blast from the past. We used silica packs in telecoms cabinets. We used to put them on the tubular heaters in the telephone exchange to dry out. We reused them lots of times. Thanks very interesting.
I made a terrible mistake using calcium chloride to dry out the car after a leak. I forgot about it and went for a drive… the calcium chloride solution that had collected spilled out into the spare wheel well and fabric. It attracts water even when wet and I seemed to have an everlasting wet spot!
Same happened to me. It's just weird that a powder can suck up so much water from the air that it becomes a liquid (oversimplified).
Yeah, that slightly gooey stuff is nasty and I suspect it even to be corrosive to metal. I used roughly about 10 bags of silica gel (each about 100 grams) in the whole car during winter pause in the garage and it kept humidity lower for about 3 - 4 months and then it was saturated. You even need a humidity logger device if you want to do it properly. And we Germans are well-known for taking it seriously.. 😉
@@phizc sugar in a sealed container can do this too if it has a slight transfer of air in/out
@@DasKmbH I imagine that it absolutely is corrosive the same way other chlorides like sodium chloride would be, being deliquescent tends to keep moisture perpetually present and the resulting salt solution would accelerate corrosion the same way salt spray would. Interestingly I find that leaving those rock salt candle holders (or any chunk of rock salt) on a surface tends to lead to this thin salt crust expanding out from the base of the chunk, perhaps it's attracting moisture and the resulting solution evaporating leaving behind a thin, expanding crust of salt on the surrounding surfaces
I have a tub of anhydrous zinc chloride at work. Or should I say I used to have a tub of zinc chloride at work, I now have a tub of brown liquid as it's so hygroscopic it turns itself into a solution, even in an apparently sealed tub!
For the zeolite, it depends a lot on what type you used. This can be optimized for a variety of molecules and temperatures, or for exchanging ions.
If you have a fairly standard zeolite there, like 3A or 4A, it should be able to absorb more than double of what you measured, but it is supposed to be regenerated at above 120°C.
Zeolite 13x can be regenerated at 90°C and has about 23% absorption capacity by weight.
The amazon stuff is fake.
I ran into this issue in the past.
I'm stunned that anyone would bother faking molecular sieves.
@@elitearbor China
@@elitearbor I first realised how much money was in counterfeiting when I saw that 1p coins were being faked. It probably cost 0.99p to make the fake but en masse it adds up!
@@elitearbor anything that can be faked shall be
No one can say that you don't put effort into your videos. That is one experiment I wouldn't have the patience for. 👍
So glad you did this one! I've been curious if there's anything better than silica gel. Bring on round 2 !!
Let's see anhydrous calcium chloride.
@@dekjet surely better, but do we have a supported version?
Quicklime in some cases. Or even those iron powder hotpacks that react with both oygen and water vapour come to mind.
@@blueredbrick yes, quicklime is very effective in removing both CO2 and H2O but it is not easy to regenerate. For all practical purposes, the very low cost offsets its absorption capacity
@@janami-dharmam A small-ish glass melting oven can be found in second hand stores and even newly bought it's nothing too extreme. The only difference is that the oven includes actual de cent insulation that does not melt easily. Take a large blok of metal forging crucible orr insulating material and have a small plasma arc in a cavity, say 100 watts and it''ll keep going up in temp until the systems just breaks melt or the fuse pops. When the heat cannot escape properly it takes very little energie influx/power to keep increasing the temperature.
Still I prefer silica gel beads or similary ceramic gels, less of a hassle. But sometimes you got to actually react the water or CO2 or others away to get the result you want.
Similarly those 'getters' inside vacuum tube tech like crts are not perse super practical but it is needed for the proper functioning of the device for longer than a week or so.
Also I'm not really liking the property of the ultra hygroscopic materials that dissolve themselves into a messy nasty mess like those calcium chloride based stuff. It's usable enough but it is my personal preference to avoid it. I've had unnecessary troubles with drying modules for drying feed gas that just turned into snot and ruined my experiments just because the person before me was apparently content with the messyness and did not bother spending a day improving that part of the system.
Having your own part of a lab is awesome so can optimize it and know what to expect.
I love these weekend drunken videos... bless you Clive 😌 we need more blue collar trash hacks! 🤣
I have always known that my refrigerator is the ultimate "Desiccant" device. I had a piece of Christmas Plum Pudding in there, and I just pulled it out, and it is hard as a rock.
I think it might be necessary to consider and compare whether each material is an absorbent or and adsorbent.
Maybe won't make much of a difference in deciding which is best at capturing moisture, but may make a large difference in the amount of energy to dry them back out again. Hopefully, part 2 of your experiment....
It may also be worth considering the conditions in which these materials captured the mositrue, temperature and RH, and how changes in those are reflected in the capture rate.
Very interesting Big Clive (as always) 👍
Hi Clive.
Very interesting, as usual.
I’ve recently acquired a Bambu P1S 3D printer. It has a sealed filament holder (AMS) which houses 4 x 1kg reels. As you are probably aware the filament absorbs moisture, and this can adversely affect the quality of finished products.
I’ve printed 7 containers, which hold Silica Gel, and these slot into the AMS, to control the humidity. Yesterday, as the humidity in the AMS had increased, I changed the Silica Gel, and this morning the humidity, in the AMS is 10%, whereas the humidity in the room is 65%, so it appears to be doing a good job.
I put the ‘used’ Silica Gel into the microwave, on defrost, for 15 minutes to dry it out, for reuse.
Your results appear to support my choice of desiccant😊.
Cheers Noel.
most useful - thanks - I also save all my small silica gel packages, and I have a portion of blue indicator silica gel, that I will mix into the clear one, to se when it turns red and moist.
This video is about the OPPOSITE of beverages!! Nice!
can you carbonate silica gel???? does it supercritically dry all moisture out of it without having to bake it? haha the world may never know
@@frogz Silica gel is an amorphous and porous form of silicon dioxide, consisting of an irregular tridimensional framework of alternating silicon and oxygen atoms with nanometer-scale voids and pores. It is these pores and voids which traps water/moisture but I suppose it could trap something else too.
Wow, LOVE that you did this test of different desiccants over a long period. Thanks!
I like the fact that the removal of water by desiccants requires no electricity but the huge amount of water that an electric de-humidifier removes from the air per day is impressive (liters). I wonder per ml of water removed what the cost difference is between the passive and active electric methods would be.
Nice work Clive.
You're looking for Activated Aluminium / A2-5,
You could also try Salt tablets as a one-way dessicant in a next test
His fingers was scarred by this desiccants experiments! Outstanding Bravery!
Best protocol for wet phone is warm dry place WITH fan pointed right at it. Air flow often makes a bigger difference
Oxidation is increased with greater airflow though, & that's what causes the actual damage.
@@nightcatarts You'd get the oxidation regardless. Oxygen will always be at ~21% outside the phone, and electrolytic corrosion may very well produce still more of it on the inside.
Water is a catalyst for corrosion and it provides spurious conductive paths for the battery power while simultaneously taking part in electrolysis -- which amounts to electrically-driven corrosion. No matter how it's done, the faster you can get the water out of there the better. And removing the battery, even if it involves a very difficult disassembly, is at least equally important if the device is to be salvaged.
@@nightcatarts There will be no shortage of oxygen even without moving air. Increased temperature will speed up oxidation for sure, but getting the moisture evaporated ASAP is a good move.
@@jamesg1367 I rescued my phone (fell in the toilet while doing what ones does in a toilet :) once by flushing my phone with distilled water and quickly remove the liquid by a vacuum cleaner then running to my already ready dried silica beads in a glass dessicator and a bit lowered presure etc. Was lucky to be near a lab. There was no way to remove the battery in the time it would self destruct by what you mentioned.
FYI: Zeolite is used in oxygen concentrator machines. Room air (~21% O2) goes into the column of Zeolite, and ~97% O2 comes out. (assuming it is medical grade Zeolite)
Zeolite holds onto water very well. So much so that even 110 degrees likely wont dry it out.
Water boils at 100
@@penguin44ca PURE water boils at 100 C. But zeolites with water absorbed is not pure water.
If you would like a simple example, make a 50-50 mix of sugar and water, and see when it starts to boil.
there are zeolites and zeolites. they are synthetic silicates
EPSOM SALT!
Try that, though you need to find a way of containing it as it will expand when it absorbs moisture.
To make it anhydrous, simply heat it to about 80 degrees for about 10 minutes, and stir it before ramping up the temperature to 110 degrees C - and leaving it for another 10 minutes, stirring occasionally.
I did this in a glass jar in an oven - so the end result may vary; but the idea behind stirring is to stop it from forming a solid hollow 'cake' which is really hard to get out, and may not have as much surface area as the granular powder you get when you stir it up as it dries and shrinks... Also you don't want to melt it...
The result is a *very* active desiccant, such that it shrinks down to about 1/4 the original size when dried, and is difficult to keep 'purely anhydrous' since it will immediately draw moisture from the air once the temperature drops below 80 degrees!
This is an amazingly useful set of data. My most sincere thanks!
While I learned that I am correct to use silica gel for my drying purposes, I learned more about what cat litter to use.
Project farm would be proud of you
would he? We're gonna test that.
I don't know, no appearance by Cousin Eddie.
Clive talks 33% slower...
@@TerryLawrence001 With a much more pleasant voice.
Clive breathes between sentences and doesn't jump cut edit it out.
Thank you, I'll dry hard to make good use of these results.
Properly dried zeolite is most effective for critical drying of process gases. On the other hand, zeolites (there's a whole range of these) can be used to remove pollutants from water by dint of being 'molecular sieves'
I wouldn't have guessed you could effectively dry desiccants in an air fryer. But I'll mention I got this rack accessory thing included with a new heat pump clothes dryer which lets you dry shoes and such in it without it tumbling around. I tried putting 1 kg of silica gel in it one day and it worked amazingly well, both in terms of quickness, ease and power consumption, now my go to method. Kinda makes sense to me though, an oven is just a hot, sealed enclosure, surely the air just saturates pretty quickly? Whereas a dryer actually removes the moist air. It's also a lot cooler around 60 °C so (most) plastic desiccant holders don't melt (eg. PLA will deform).
Interesting point about the air fryer.
Ovens are not a sealed environment. They have a small vent that typically vents through the back of the range near the dials, or through a rear coil top depending on model. Steam and hot air escapes through this and fresh air is drawn in.
That makes a lot of sense, but is 60C hot enough to dry it out in a single drier cycle? Clive was suggesting even 90C from the little heater unit he used might not have been enough, and while there's an additional boost from using a heat pump drier which directly dehumidifies the air as it cycles that still might not be enough to fully dry the desiccant out
@@JourneysADRIFT Because you said "range" I assume you're from North America where gas burner ovens are common (they're now banned here in Australia for air quality and fire hazard reasons). My understanding is almost all gas ranges vent the oven space because they have to burn a fuel inside, but in most countries electric is vastly more common, those don't vent the oven space apart from for pressure equalization. Almost all modern ones do have fans and vents on them but that's just to cool the electronics and the outside of the oven in the cabinet and sometimes the front glass. If you do try to dry water logged things in an electric oven you'll find you have to open the oven door every so often and when you do the built up steam is often visible to the eye.
@@WizardTim Range doesn't mean gas specifically, just the oven/cooktop combo. It can be any flavor. My electric one does have a vent in the rear that is for steam/vapor to escape.
Maybe you should stick your phone in cat litter and hope you get to it before the cat does. 😂
Cat won't do more harm to it than already happened by getting it wet with the battery installed.
Us humans always have our phones in the bathroom, now the cats can have our phones in their bathroom
@@Tinker001 Cat urine is in fact exceptionally corrosive, which is something i know from laptop repair. Because they love sleeping on a warm keyboard and leaking a couple droplets occasionally. Also prefer not to have the smell when repairing things.
Is the urine from the Eveready Cat more corrosive? That has to be their secret electrolyte
@@SianaGearz I've had a keyboard sacrificed to cat drool (she would curl up next to it when I was working--took out F1), but I am very glad I've never had to cope with the smell of hot cat piss.
Great, comprehensive test.
I use silica cat litter in my outdoor electrical boxes to fight moisture and in sewage treatment plants, moisure comes with agressive sulphites or sulphates that spoil copper wires and contacts. Cat litter for me justifies its price many times over. Silica gel ir rare and expensive. Will check out bentonite litter if i find it in local shops.
No idea when I might use this...but I love the fact that you checked. The next obvious question, will the bentonite carbonate?
Yes, it would be interesting. If drying as much as you can before you start the experiment does have a better result.
I've heard that chemists and the like use 200°C to dry glass and other equipment. Glass is hygroscopic if you get down to ppm of caring.
Yep and "sacks down" also
Cool, I never put that together... But I guess it makes sense, given glass is also amorphous silica. Or is silica gel just puffy glass?
The bentonite/felight comparison is very well taken. A final comparison column that would be very useful is cost - how many ml of water absorbed per penny of first cost. I would expect the rice to be the cheapest, but it presumably can't be re-used as many times as the mineral products. You put ez-cook rice in salt shakers, partly for its dessicant effect, to protect the salt from clumping, but also partly because the large grains help to avoid flow problems.
I liked this video, very educational, I don't have the patients to test like this, but I would like to see two additional things carried on from this video:
1 - Drying the materials past the 90'C limit, the air fryer is ideal for this as it has high heat and decent air circulation, 160'C is what I use for my colour changing desiccant that I sit in a old metal pie tin, with drying time taking between 10-25mins depending on how much I'm drying.
2 - I'm curious about where in the chart those cupboard style desiccants that come in a plastic tub that you peal the silver foil off. I use these in my car.
3 - How about salt? Baking soda? Laundry powder:? That stuff oes like rock 30seconds after you open the box.
When I saw the preview thumbnail, I honestly thought this was a Project Farm video. LoL!
Good video.
Although drying them out at a higher temperature may show their maximum potential, I believe your results are still accurate. Not only was it a consistent drying procedure, it's much more realistic to what the average power-user would be doing. I mean, sure, we could all dry them out in a used toaster oven, but when you already have those desiccant dryers, I think most of us are likely to take the easier route and use the dedicated dryer that we can leave on for the day. I think it would be interesting to see their maximum potential, for science, but these results are much more relevant to the common power-user.
How does the cost break down? Cat litter seems like it would be a lot more economical than silica gel. Thanks for sharing your results.😊
i use felight in porous bags in all my shoes. my shoes no longer stink like hell warmed up. best discovery ever!
Another desiccant is calcium chloride, aka with the corporate name in the US of "Damp Rid". It actually liquifies it absorbs so much moisture. Reusable too. BTW, did you notice the cool electrostatic effect the plastic bag had on those zeolite prills? First time I ever saw that effect was with those tiny (carbon?) prills/balls that you can find inside many old hard drives. I think they also were used for desiccation. This was an interesting video Clive. Thanks.
Interesting. I bought some "Moisture Traps" from Poundland in the UK and the one I put in a 3D printer enclosure is now totally liquid (old damp house in Wales!). The instructions tell you to dispose of it. I've just noticed it contains calcium chloride, so does that mean I can convert this disposable product into a re-usable one?
@@EcoHamletsUK Yes, the calcium chloride solution can be evaporated in the microwave or on a tray in a low heated oven. Scrape up the dry flakes and start again.
@@EcoHamletsUKsame here. I put one in my room It’s filled with water, I’m surprised I don’t have a mold issue
Another material is the stuff they make disposable diapers (nappies) with. Amazing absorption, though I don't know how good they'd be for drying things out.
Clive, Excellent video as usual keep on making stuff like this.
Aluminum Oxide is a well-known desiccant. I bought 10 pounds a couple of years ago. I use Mason Jars with mesh lids and swap them monthly to keep my filament container dry. I dry the old desiccant in the Mason Jars in an oven and then use a regular lid.
I wonder what the “cost per ml” is for each?
Great video as always!!!
Nice Clive unban just in time before my bday tomorrow turning 33. I love your tests you won't cut corner that why I love your videos. Q
This video was really informative. It would be great too see the difference if they were dried really well first. I'm also curious what the rate of absorbtion would look like withen the first few days, or even hours. This could be useful for drying objects.
Interesting. Thanks for following up with this.
We're all on the spectrum for sure.
Great results, i expected the zeolite to do better. How about anhydrous magnesium sulfate, calcium chloride, etc.? From what I understand it'll take a lot more energy to "recharge" but may absorb much more humidity...
Zeolite probably wasn't properly activated it's typically dried somewhere around 250C at only 90C as in the video I'm afraid it won't dry much at all.
Thanks once again for a wonderful video. I like your videos. Keep up the good work.
Hi Clive, Zeolite binds water quite tightly (up to 30%) in its structure so in order to 'dislodge' it out again, you really want to go a bit higher than 90°C. In our lab, we used to bake the zeolite at 120°C. I think, industrially, they go even higher to get really 'activated' zeolites.
It's quite important to check which zeolite you have; usually it's the 4A stuff.
A good test for zeolite dessicant; take 10-20 grains of (cool, dried) zeolite in your hand and put a few drops of water on it. You should feel them heat up noticeably. If you don't feel that, your zeolite is maybe the wrong type or degraded;
Try the super fine silica used in water pillow type humidifiers. Also try putting the whole apparatus in a sealed container ported with one of your solid state dehumidifiers. Check to see if you can increase the saturation, and also see if voltage is generated due to the humidity gradient across the membrane of the solid state dehumidifier element.
Moar interesting than I had imagined Clive. Thank you 🙂
Activated Alumina ...
@@AnX8765 Nope
@@AnX8765 nah, I do find it funny. I sensed the humour, all is well.
I work in a lab with ultra-high vacuum chambers (made of steel), and to achieve ultra-high vacuum you have to bake (=outgas/degas) the chamber at 200°C for two weeks, which is the temperature and time most people agree on. I think this is because there is another desorption peak of water at about 180°C, the main peak being at about 100°C (for obvious reasons).
Being a thermal-activated process (as you might guess), it is logarithmic. That means you can do bake-outs at 60°C or even at room temperature when pumping, but it will take months or years instead of days at 200°C to achieve the same results. I am not saying that you got this all wrong because your results are interesting, but I clearly would recommend you drying the stuff at more than 120°C in a kitchen oven instead.
The DampRid products in the US use calcium chloride. Also, I live on a dirt road. Twice a year the state sprays this in front of my house to keep the dust down. It's greatly appreciated since the road is on a steep mountain, and some like to spin their tires to make clouds of dust.
Very good! I have a personal interest in this (you do that a lot with your vids - Ms.Flambeaux excluded :D)...
I have a hyper-baric compressor that can easily go to 4000lbsin2 (i.e. ~300 bar) and the target for the compressed air really does need as close to zero moisture as possible to avoid damage. There is a two stage piston in the cylinder with a first stage "basic" compression, and then a second stage "final" compression that has a tiny "needle" piston with massive cyclinder walls. The problem comes in with moisture in the air at these pressures and dimensions and it gets really hot when working hard - 100C+ easy. I run the input through a series of cotton "swabs" that take out any obvious moisture and there is a gravity-fed bleed valve that needs opening several times during a session and always produces hot emulsified oil & water.
The final output is then fed through more swabs (to remove oil vapour mainly) and then into a thick-walled cylinder which is the final drying chamber. Inside is an acrylic tube about a foot long filled with colour-changing silica - it starts out orange and changes to dark green when it has absorbed moisture. The tube is a loose friction fit so as not to burst it in the high-pressure air (i.e. pressure is the same both sides of the wall) with an O-ring at the far end so the air can't sneak past but rather has to pass over the silica. The output air should be very dry but I wonder how quickly the silica will absorb moisture? That said, the silica is still orange and I would have thought if my pre-drying was shabby, I would at least have seen some disclouration (it does in normal air). I have seen "Molecular seive" available for drying but I don't know what the material actually is for reference.
From your figures, the 337g of silica you started with seems a bit more than in my acrylic tube-ful (never weighed it but will now) and rough maths says it was taking out ~25ml per week, which, say, is ~4ml per day or 160ul per hour... which now I write it doesn't sound too bad. I wonder if the forced airflow and huge pressure will make any difference in my case. The pessimist in me is mindful that high pressure tends to squish the water tighter into the air molecules (hence high pressure = fine weather) so maybe the final drier is not as effective as it might if it were pre-drying - i.e. on the air intake somewhere. Unfortunately I have no way of measuring.
So my concern is not so much "quantity" but rather "how quickly"... I am going to start with dried silica (yes you can re-use it) and do before and after measurements. I have to spend some time thinking about what constitutes a good test... time or volume of air - this latter is considerably and I would need several goes at it just to let the compressor cool down.
Thanks Clive... inspired me to do some tests of my own. Maybe even video it and post it.
Cheers
h
How dry do you want it to be ? Sometimes I'd use quicklime pellets/rocks in a closed glass desiccator with or without vacuum. Depends on what you try to dry. Once I had to dry ammoniumacetate to form nice dry pure crystals, well that needs a closed system with the quicklime but no heat or vacuum otherwise it will either melt or sublime. Water vapour and also the carbondioxide that is present in the air reacts with the lime to form the hydroxide and carbonate from the air. The quicklime can be regenerated by calcinating it in an high temp oven such as uses for glass working.
And yeah please use both the mass and volume for comparing different methods of drying agents.
A wet phone would brake if under full vacuum but nested in silica drying beads in a glass desiccator and a bit lowered pressure and an infrared lamp pointed at the setup to ,say, 40 degrees C does wonders.
Also its important to know which type of "wet" is the culprit. Rainwater is ok enough to put it directly into the system. But spilled beer or soda or even tap water is nasty. Then asap spray and rinse with distilled water quicly to get rid of salts and use a vacuum cleaner (with care other wise the speakers etc will pop ) for example to remove the bulk of the liquid. Then to dessicator and hope for the best. An alcohol solvent the 100% pure type either methanol ethanol or IPA can also be usefull for cleaning and drying but in the case of a phone I bet it would damage it.
It is upsetting that batteries are no longer easily removable from devices nowedays, it would prevent a lot of damage if you could can remove the battery in a hurry and then also do the rinsing and drying ritual.
Good test...
What is missing is at what humidity level it still pulls moisture. In other words, how dry can it get the materials. 💛
I was asking mylself these questions yesterday !!! Thanks for this video !!
Nice, interesting, good methodology! Thank you! 😃👍
- rice: THE standard desiccant for salt in East German restaurants near lakes or the coast
- silica: I expected it to be the best, there must be a reason why everyone uses it. If you have leftover silica bags from your purchases in leather or electronics: throw them into a drawer where your jewels or your silverware is. It's the best in avoiding blackening of jewels and silverware!!!
- bentonite: Used for the clarification of non-vegan wine and apple-juice - bentonit is mixed into the beverages for catching impurities, egg yolk is mixed in and lets the impurities with the bentonite fall out and settle in flakes. Is it used as an oil catcher in filling (gas) stations? I'm not sure.
- zeolite: An ingredient of detergent powder for laundry.
- What did the USA use as desiccant for army and astronaut's food? Little permeable bags with iron powder - it absorbs water and oxygen independently and transforms it into rust.
Thanks for doing this Clive. I have a couple of questions:
Were these tests run at the same time (so that the RH was the same for each test)?
Do there media perform the same repeatedly (i.e. after re-drying and re-using)?
I'm sure a higher drying temp would give better dehumidifying results but this is fine for real-world use.
I appreciate your work, cheers.
Tests were run at the same time.
You know we're very keen to see the Excel graphs, BC! Although obviously non-reuseable, Calcium Chloride granules are a widely - available, VERY good "domestic spec." desiccant. Phosphorous pentoxide is amazingly good (but reasonably hazardous - phosphoric acid isn't nice stuff!)
Back in my caravanning days, I used trays of calcium chloride crystals to keep the moisture at bay. In a week or two they would have completely disappeared, leaving behind a tray full of (not) water. They were only a pound or so from Home Bargains or B&M.
While I scoff at the whole 'submarine phone' dried in rice, I ALSO scoff at the 'warm dry place'.
Personally, I throw the ENTIRE phone into something like anhydrous methylated spirits (which is basically denatured ethanol) and give it a real good 'swim' in the stuff.
Any water will RAPIDLY mix with the ethanol thereby DRAMATICALLY 'diluting' the amount of water left in contact with the electronics.
Once removed from its _BATH_ in solvent, then get your wife / girlfriend etc hair dryer and put it on fan only (i.e. no heat) and throw the phone in the airstream to rapidly evaporate any remnant alcohol.
A BONUS is that this will give it a half decent clean at the same time and the half-arsed flux cleaning that was done at the factory is improved upon!.
A potential DOWNSIDE is that SOME plastics don't overly like ethanol (but such plastics don't get used on phones, so you should be fine).
I know it SOUNDS counter intuitive to DRY something by first fully immersing it into a (wet?) liquid, but I can guarantee you that within a few minutes, it will be SIGNIFICANTLY dryer than if you'd placed that phone in a bed of rice!!!
NB: If the initial 'swim' the phone took was in sea water (i.e. SALTY), then it's best to first drown it in distilled water a few times to rinse out as much salt as possible. (Once again, this SOUNDS counter intuitive). Pure (distilled) water does not conduct like salty (impure) water does. It's all those impurities that will destroy your phone rather than the water itself. As the water component evaporates, it effectively CONCENTRATES the remaining (salty) impurities!
Two notes of context for others reading this:
1) Conformal coat can be removed by some solvents, and so tin wisker susceptibility or weatherproofing can be affect. Ask me how I know…
2) Salts are generally insoluble in ethanol, isopropyl, etc.. This is why you use distilled water first.
@@tylervanderkley
I agree that conformal coating is often easily dissolved by many (most?) carbohydrate solvents, I've not seen any mobile phones that actually use conformal coatings. (But that does NOT mean such devices don't exist!). The conformal coating I use is handy in that it doesn't need to be removed if any 'rework' is required on the board. (Just apply another coat once it's repaired)
NB: Some people aren't aware of the difference between solder mask and conformal coating. Solder mask (often green in colour, but available in almost every colour these days) is applied to the bare board BEFORE any components are added. One of its many purposes is to avoid solder bridges. There are intentional GAPS in the solder mask to expose the pads that the components are soldered to.
Conformal coating is (generally) applied AFTER all the components have been soldered to the board. It's purpose is to seal the ENTIRE board (including the component pins that have just been soldered) from exposure to the elements (such as humidity etc).
My last quasi-humorous comment explains all I was 'taught' by a wise old man about waterproofing electronics that have to live outdoors...
1: Spend an inordinate amount of time coating everything and sealing it up nice and tight into a suitable enclosure.
2: Once that has been accomplished, bore a fairly decent sized hole in the bottom of your newly sealed enclosure so that all the water that WILL get in has somewhere to drain out of!
YES, it sounds ridiculous, but whenever I follow that process fully, the thing lasts. And when I don't precisely follow that process, it will only last a few months at most!
There are a LOT of different types of zeolites, but for the common ones intended to adsorb water, you really need to dry them between 200-220°C at least. (Some kinds of molecular sieves even require overnight drying under vacuum at 300°C, immediately before use!)
Also keep in mind that "drying" doesn't just mean "sucking up" liquid water or absorbing water from the air at high relative humidity.
Unless the drying agent chemically reacts to destroy the water, there will always be some amount of free water left over, because the water adsorption/desorption processes will eventually reach a dynamic equilibrium. This is why adding multiple times the mass of dessicant, that you theoretically need to adsorb/absorb all of the water in a fixed volume, results in not only faster drying but also gives you a dryer end product.
For example, a good zeolite will adsorb water from fluids even at relatively high temperatures (50-80°C) and will be able to maintain single digit PPM levels of water contamination at equilibrium (assuming a large enough excess is used).
At the other extreme, rice will actively make a truly dry fluid *much* wetter (going from ~10 PPM of water to > 1,000 PPM), even if you dried the rice at higher temperatures and used it immediately after.
Some Zeolites just "bind" the water much stronger than any other reusable dessicant (hence the high temperatures needed to dry them) and they can therefore effectively dry a larger variety of materials (i.e. you could use 3A molecular sieves to dry rice or bentonite clay, but you can't do the reverse. This is important when the thing you're drying is itself hygroscopic.)
How much energy does it take to reconstitute the dessicants? Could one of them be cheaper than the rest to reconstitute? For indoor spaces, I'm thinking the most cost-effective means to dehumidify might be heat recovery ventillation but I suppose it depends on local climate.
My cat said thank you.
Good work, making it clear which worked better. But, I can't help but wonder how just plane old salt or baking soda would stand up to these results.
Salt turns to liquid and doesn't really absorb moisture below a fairly high humidity.
Would it be possible to test Sodium polyacrylate as well? You might have to use less since it can really expand but it might be an option to look at as well! Keep up the awesome vids!
Silica Gel in much larger quantities is used to stabilize humidity in an area over time. Say you had a museum of textiles and you want to keep the humidity at a certain point. The silica in many kilogram quantities is used to manage swings in humidity in the various display and off display area.
Good test. I will say hot air absorbs more moisture than cool air. So in an ideal situation, you would heat the entire room to adsorb all moisture from the room into the air and then push it through the drying media. But your little heater probably helped a bit, Im just curious about the rest of the room. I.e. a humidity measurement from the room would be an interesting thing to follow. But it would probably have to be a relatively small room to see any real changes. Good job. I love it.
Never in a million years would I have thought I'd be watching a Big Clive video about desiccant. I need reusable desiccant for my 3d printer filament storage tote. After seeing this video and seeing how well silica did, I might just get some silica. I'll probably spring for the orange color changing silica (get the orange because its non-toxic as opposed to the blue which has cobalt).
Activated alumina works much better. It keeps pulling moisture out of air to much lower levels than silica gel can. I believe silica gel works faster, until it just stops pulling moisture.
Activated Alumina is a very reusable desiccant, I personally don't care about the reusable aspect so I have been using Calcium Chloride. It can be bought for as little as 3 usd per pound or 450 grams so its very cheap and its cheaper to buy more than to dehydrate it although it is technically possible. Plus it turns into hard water when its fully used up, so its very noticeable when it's all used up. It keeps my nylon filaments extremely dry.
this and the LHC, all the science a guy needs
Cody’s Lab too!
@@canadiangemstones7636 I have heard that mentioned before, perhaps i will give it a look.
Yes, dry them out. Try different temperatures as well because zeolite may need higher temps.
Interesting, volume versus weight. Does the container stop the dessicant from absorbing moisture as by volume the dessicant can not expand as it is full to the brim? Do they also then have the reverse effect, if they are saturated and not replaced will they then release moisture back into the air? Interesting subject and experiment.
Activated Alumina and magnesium sulphates would be nice additions. You can get magnesium sulphate monohydrate (MgSO4•H2O) by heating Epsom salt to 120°C and anhydrous magnesium sulphate by heating to 250°C. Epsom salt is magnesium sulphate heptahydrate (MgSO4•7H2O)
Ramp the heating slowly and give it time to soak. I chucked a pan in a hot oven and it melted down first and ended up being a solid mass when I was done. The slow ramping allows for the moisture to drive off vs puddling out and left me with a fine dry powder.
Good info!
Thinking of cutting all the silica gel packets I have here, drying them somehow, and leaving on the car that is parked underground... as I don't drive much, sometimes I get some fungus when I go give it the routine run around.
The reason to put a damp item in a descant is not to absorb the moisture directly but to render the air around the item dryer to evaporate and capture more moisture from the item. A deep baking pan with (clean) kitty litter in the oven for an hour and when it cooled enough you put the item on top with a air gap and the pan in a air tight container/bag to give the item a elevated chans of drying out. I would how ever suggest that immersing the wetted item in pure ethanol/alcohol would "rinse" the water out by dilution and shorten the drying time as alcohol evaporates faster than water, and may clean water residue from the item. You could then use the desiccant to speed up the drying further. If it will save a phone dropped in the water or not will largely depend on if the water shorted out and burned any part of it. A phone with no battery put in clean water has a high chans of recovery as does most un powered electronics, I once carried a crt monitor home in pouring rain with no box and after removing the cover and putting it in front of a fan over night it worked just fine. Salt water is a different story, chans of recovery is slim to none.
Could call this "project desiccant" great homage to a beauty RUclipsr.
Also always super impressed with your single shot videos. You are a super well spoken person.
Clive, what I would love to see is how good they are at retention of water, for example, I have been told that Carbon Fibre 3D printer filament will actually pull moisture out of silica gel whereas it wouldn't from Zeolite so for drying purposes, silica gel wouldn't advisable in this scenario unless the silica it was perfectly dry to begin with
If you do another round, I would love to see Activated Alumina. Supposedly performs better than Silica Gel.
*Edit* He mentions it at the end.