Supercritical fluids are useful for all kinds of stuff. For example, supercritical CO2 can remove caffeine from coffee without pulling out anything else. Check out our shorts content for more about that coming soon.
There are, I think hundreds, if not thousands, of similar compounds to the PFAS molecule shown on the white board. Companies are phasing some out, but are going to still produce others. This needs to be known about, and opposed. Different forever chems could be even worse.
The science and probably loads of applications behind it are really cool. Thanks for explaining. However when it comes to solving the salted earth problem that is pfas, a new way of disposal is but a drop in the ocean. If we can find a way to seperate all the insects from every part of dirt on this earth we'll be just a tiny step closer to actually getting the pfas out of the environment. And being able to destroy the part that really matters.
I like the honesty of this channel. A lot of science media over-hypes things for the clicks. This channel is pretty honest about the likelihood of these cool reactions becoming actual solutions to our problems.
It's a weird thing this channel. Google, American Chemical Society, and you will see they are actually a lobbying group for the chemical manufacturing industry. That though does come with a caveat, they hire ACTUAL chemists, and some of these chemists, get to do a TH-cam channel because it is good PR to educate. I think they get to do whatever they want really and it shows in the videos that they are actually having fun doing the science, so I have watched for years. Always good stuff and I like this guy especially because he knows a good gag.
This is the only well researched videos about pfas i've seen on the internet so far. Even mentioned that firefighting foams are the main culprit and not pans. This video should have a lot more views.
You might want to check out a more accessible and possible method called _aquamation._ This is a process where sodium hydroxide is used to reduce the body to material that can be safely flushed unto waterways like treated sewage is. (Probably even safer than sewage treatment.) Aquamation turns the body liquid. I recommend looking up Caitlin Doughty of "Ask A Mortician" for more info.
I don't usually comment, but I have to say this is fantastic scicomm. Came for the PFAS, stayed because I learned so much about supercritical fluids. Loved the theater-style demo in the kitchen. Makes chemistry relatable!
I was warned about the extreme dangers of HF in electronics school. Our instructor had been a chemical safety officer at Intel. He knew about the OG bone hurting juice that is hydrofluoric acid.
Was he missing a finger? I knew a guy from back when I worked there that didn't follow safety protocol and accidentally exposed his finger to HF (back in the 90s) and didn't know until he woke up in the middle of the night with strong pain and ended up needing to get it removed later. HF is no joke!
@nombi5456 No, but I think he knew the guy that happened to. The initial treatment is to put a calcium gel injection into your BONES, and there's nothing they can do to make it less painful. If that doesn't work, then amputation. If you get HF all over yourself, there's nothing that anyone can do.
HF varies a lot in danger with water content. Dilute HF is used as a glass etching solution by artists without much trouble. Anhydrous HF is truly awful stuff to work with.
10:25 We may not have supercritical water cremation, but we still have regular water cremation lol (Some states allow you to basically pressure cook a body with lye into goo, which uses way less energy than fire cremation, and technically you're compostable at the end of the process)
I Sweden we have a recycling fee on bottles and cans. Shouldn't be to difficult to have the same on pfas products. The paper recycling from newspapers is debited when you buy the paper etc. The only big issue I can see is to stop illegal exportation. The threat of stuff like pcb is still fresh in most adults, shouldn't be too difficult to get something like that going.
Nice idea, but not quite aligned with reality I'm afraid. The main contamination sources so far have been insufficiently regulated industry (so whether that's still a problem depends on where you live) and firefighting foams. Which is a problem because since there are no viable alternatives at the moment, you have to decide between contaminating the ground vs. letting people die. Not a choice I want to have to make. Household contamination is also an issue, but mostly comes from waste water from washing textiles, so incineration is obviously not an option. The concentrations are so low that until a few years ago, we weren't even able to reliably measure it, let alone clean it up. And for incinerated solid wastes, if i recall correctly the main problem isn't air pollution but waste ash being used in fertilizing products. There is no pretty solution. No pfas means people die and essential tech stops working, but in return we contaminate the environment. Imo the only reasonable thing we can do right now except do more research is avoiding unnecessary sources of contamination like waterproofed textiles.
While HF is certainly scary as is, you hit it on the nose at the end, a little cheap base like NaOH for example and you have NaF (toothpaste fluoride) and Na2SO4 (food additive). Also Both H2SO4 and HF are industrial valuable chemicals. It might be worth finding ways to recycle them back out of the process but probably easier to just have a base-adding second phase. BTW, if you think those are scary, go look up ClF3 and FOOF. They make HF look like a cuddly kitten..
@@Ice_Karma : I'd assume "Ignition!: An Informal History of Liquid Rocket Propellants" by John Clark. It is an excellent book that is full of stories containing sentences like that.
@@BrooksMoses An excellent idea, and the origin of one of my favourite phrases ("engine-rich exhaust"), but I just checked my full text-searchable electronic copy of it, and, alas, it doesn't contain the phrase "vehicle assembly building", and the only match for "concrete floor" is unrelated. Thanks for the suggestion, though. 😻
One of my favorite uses of supercritical water is supercritical water oxidation for power production. Basically you pump oxygen and fuel into your supercritical water reactor and it becomes an internal combustion steam engine. It's very hard to do and the power output is limited by the amount of input energy you need to get it running. But it means that you can in theory create an engine that can use anything organic as a fuel source - wet biomass, dry biomass, factory waste, sewage.
Very interesting, the absorption would absolutely help concentrate the majority of the pollutants into a liquid slurry I’d imagine? This could be very helpful in my work with mycoremediation, or fungal bio degradation. Fungi possess the unique ability to break down forever chemicals. These are mainly white rot fungi that can do this, due to their ability to break down large chain carbon molecules like lignin. They employ the same techniques and methods to break down the PFAS emitting peroxides, ligases, etc.
Just found out about supercritical water remediation while researching exactly how bad the foam we still use is, and how hard l should be pushing them to switch to something else. I was glad to see that there is a scalable process for breaking this junk down, because there is so much of it. So much. There's a few thousand gallons at my facility alone, and enough has been flowed at the training center that the ground suds when it rains.
This legitimately sounds like the job for one of those modular micro reactors as you could generate a lot of energy in a remote location for public safety. Maybe a Micro reactor manufacture could donate one of their products as a tax write off and as a test bed? If you made the acids available for free companies would be lining up to talk it off your hands the way it's done with used cooking oil, road millings, and scrap metal. Then it's no longer a waste issue but a logistics problem. Perhaps you would build this PFAS disposable facility where they would have otherwise produced the acids?
SCWO is definitely a good way to go about dealing with PFAS, especially with surrounding COD to drive it. Look into HALT, EO, plasma treatment, and UV activated advanced oxidation techniques if you want to look at things even more creative
Concentration is another parameter that affects the choose of treatment method, ppt, ppb and ppm level are more difficult to treat than that of high concentrated solution.
My friend plays tennis next to a car detailing plant, she asked me what was in this 4 gallon drum. I came to have a look, it contained aqueous hydrofluoric acid. It was on private property, not much could be done, it wasn't leaking or anything. It dissolves oil and grease (amongst other things) and is good at cleaning cars.
Can someone elaborate why supercritical water is a non-polar solvent? The only thing I can think of is this being due to very rapid rearrangement of the molecules and hence, averaging out the dipole moment? If true, does this general concept apply to (mostly) all supercritical fluids, do they all act as if non-polar?
We really wanted to include that in the video, but haven't been able to find a good explanation for this. We've come up with several hypotheses, but wouldn't want to just speculate in the comments. Let us know if you find any info!
Yeah, that's a good question. I don't think it is known for certain just yet why that is. I wondered if the pressures involved might be able to overcome the forces involved that dictate the bond angle. Apparently this is wrong. Very wrong; Its not even close. The forces involved in maintaining the bond angle are great. One of the more straightforward and simple theories put forth has to do with the expected (calculated, estimated) value of one of water's properties to be at those temperature and pressure regimes. And that property is water's _dielectric constant_, or the ratio of its electric permittivity to the electric permittivity of a vacuum, also called simply the "relative permittivity". Permittivity is a property that affects the Coulomb force, or the electrostatic force of either attraction or repulsion between two point charges. It is the Coulomb forces of water's hydrogens and oxygen, along with its bond angle, which introduces an asymmetry in the molecule, which is responsible for its polarity. ANYWAYS, water has been tested over a wide range of pressures and temperatures. "Ah, so the relative permittivity must decrease with temperature and decrease with pressure," I thought. I thought wrong. Water has been found to: decrease relative permittivity with increasing temperature INCREASE relative permittivity with increasing density ...so that means the relative permittivity stays about the same, right? ... RIGHT!? Again, I was wrong. There is a large region in which water is considered supercritical, but the supercritical region being considered here, both in the video and in discussions of this effect is in the regions of very high pressure only (while the temperature may be somewhat more variable). And it is within this region that water is calculated (I don't think it has been directly measured, as that could be somewhat difficult--although I could be wrong) to have a relative permittivity in the range of 10 to 25. By comparison, water as we are used to encountering it (room temperature at 1 atm) has a relative permittivity of 80. Values of 10 to 25 are similar to those of dipolar liquids, such as acetone or ethanol, under ordinary conditions. And this, seemingly, explains it... EXCEPT THAT'S WRO--Naw, I'm just fooling about. This does indeed conclude the explanation, according to the hypothesis.
it's still polar (form what i've found), but as said in the video, it's acting in between a gas and a liquid. I think than when water molecules have a ton of speed (because of the high temperature) they cant rearrange around an ion to dissolve it as they do in liquid state, they go too fast and the water solvation sphere simply breaks. The reason because they dissolve non polar molecules i think it's the same reason, it's acting like a gas. The molecules go so fast that the non polar molecules are kicked of and dispersed in the fluid.
I could just look this up, but 1) How are we going to isolate PFAS to a high enough purity to not cause other reaction issues and unwanted by products? And 2) if we can separate it, isn't there some way of recycling it into more or different PFAS materials? Eg: why can't fire fighting foam just be a soup of reused PFAS and viscosity-controlling agents and such? 3) Why don't we just use the HF as a chemical feedstock, since we have to mine fluorite and mix it with sulfuric acid to make HF anyway?
Agreed and their is a practical solution to capture both HF and sulfuric and sulfurous acid from the super critical oxidation reaction it’s being used today to control the waste pyrolysis of fluoridated coatings over medical and carpet treatments and called Alterin technology and used in the UK today trough upcycling global
Hmm does it have to be water tho? I mean, supercritical Xenon seems to be quite easy to procure. Would it not do the trick? Or some other substance perhaps?
I appreciate the possibility but it's too late for me... I don't think this reaction is going to get rid of the PFAS in my body. Also, who's going to pay for it? Dupont may have made a killing on selling it but I have a feeling it will cost even more to get rid of it.
I’ve been so fascinated with supercritical fluids since first learning about them. Very surreal. I never knew water’s properties changed so dramatically when supercritical. I also find the bathtub in the basement quite curious. 🤔
CF is the strongest natural single bond with carbon. CN is stronger but with two bonds. If you take per bond it would be lower. Still B-F, Si-F and H-F are stronger... all Fluor based though.
How does it compare energy wise to destroying these chemicals using plasma? Also, sCO2 will dissolve fats and oils. Can I use it to make the perfect (low fat) chip?
@@KaushikAdhikari yes. I'm saying it already has recognition. There are people working on getting it for smaller installations, as he said. But it's not there yet.
Oxidation by supercritical water releases Hydrofluoric acid which could be neutralized by lime, calcium hydroxide. But the real problem is to extract the PFAS from waste water so as not to have too large volumes to treat. Extraction would logically be possible with a perfluorinated polymer absorbent.
Now that some states have established maximum PFAS concentrations allowed in drinking water, I hope affordable technology exists to remove it from municipal water systems.
HF has the acidity of citric acid (lemon juice) so the acidity isn't the real problem. The problem is that it's a molecule so little that can go throught gloves and skin easly, and when it's in the body it bonds strongly to the calcium in your organism and therefore can't be used for muscle function, leading to a cardiac arrest and death.
@0:35 wait, the way you say this makes it sound like a very specific thing that only happens to a select group of elements/molecules. I thought everything could be a superfluid so long as it doesn't decompose under the conditions. (Whether we can produce the conditions is the question). But I can't think of an element that can't do it , in theory, and the same for most simple molecules too.
where this process is made? If it's made in a metal container. does the supercritical water corrodes the metal and produces H2 that leaks throught the metal and weekens it?
L'oxydation par l'eau super critique libère de l'acide Fluorhydrique qui pourrait être neutralisée par de la chaux, calcium hydroxyde. Mais le vrai problème est d'extraire le PFAS des eaux réiduaire afin de n'avoir pas de trop grands volumes a traiter. L'extraction serait logiquement possible avec un absorbant polymère perfluoré.
Can CO2 on its supercritical phase serve similar purpose with less drastic pressure and temperature parameters? Thanks for the video, you're doing excellent job ❤
Supercritical CO2 isn't useful for oxidizing PFAS, but it can selectively remove caffeine from coffee. We have a short coming about this in the not-too-distant future, stay tuned.
So water is clearly just showing off at this point. Water has already won the award for the #1 most dynamic, useful, diverse and amazing chemical compound of all time, and in two award categories: Solvents, general and chemical compounds essential for life. Or at least it is in my book, anyways. Water could have easily retired once the 10th phase of water ice was found. And yet, they are up to, what, 18 now? 19? What a total powerhouse! Water just loves flexing on the competition, I guess. I once said that if I was the competition, I would want to cry, until someone pointed out to me: "Cry what?" BAH! Yet another W for water, that jerk!
Super-critical water cremation sounds like a fine idea except for the high energy costs and encouraging a commercial process involving high pressures to go into a sector that's not accustomed to them. Fire cremation requires an absurd amount of energy and generates a lot of CO2 because, well, burning, and also tends to emit a shocking amount of mercury, because of fillings. Super-critical water cremation avoids a lot of that, but replaces it with straight up energy costs and a pressure vessel just desperate to have a BLEVE
Lost me in saying industry doesn't like SO4 and HF. HF may not be as common, but they're still frequently used. So what's the issue with recovering the acids to sell back to industry?
@@ACSReactions Oh, ok. Seems like an obvious engineering issue, one we've already solved at least partly, making your statement a little, well....... I mean, sure, we're able to produce bottles of fluoroantimonic acid, and while containers may not be at extreme pressures or temperatures, we've still figured out how to ship it around the world safely. According to the molecular electricians I know, FAA is much scarier than HF and SO4. If only it were a matter of lateral thinking finding lining substances inert or resistant to the conditions present, could be made cheaply sacrificial, or electrifying the device to control corrosion somehow..... Nah. That's silly. Defeatism for the......win?
Supercritical water does not hold salts. Wonder if it would be worth it converting salt water to fresh at extreme depths and then using the flow of fresh water to power the process. Probably not but it is a thought.
i feel like if they went to the people that build nuclear powerplants they could get there costs down lots of high pressure water runs through nuclear plants and im willing to bet it can handle the preasures and temps they would need to hit bonus points if they use it in a cooling loop for an actual reactor but i wouldn't considering how corrosive the reaction would be over time to heating system i would be suprised if it could last more then 10 years before the entire thing needs to be replaced
Wait wait wait. If water behaves like a non-polar molecule when it's supercritical, does that imply that its polar character is only because of autoionization? That sounds silly because it would imply that water autoionizes even as a subcritical gas but what explains the non-polar behavior at supercritical temperatures and pressures? Does the bond angle change? I suppose water would be expressing its vibrational modes at such temperatures but is it because the sawhorse (sp3 hybridized oxygen) is able to flip the hydrogens about its center plane (dividing the hydrogens and electron pairs) at a high enough frequency such that it's approximately linear? That sounds much more plausible than an autoionizing gas. I suppose by that logic, if oxygen is rotating fast enough about 1 of the 3 primary axes, it would also look non-polar. Woah. Surely there's literature on that. Anyone have a good reference?
What does it even *mean* to be a "base" in supercritical water? Water dissociating into ions is the entire basis of pH, if thats not happening any more then your sodium hydroxide/bicarbonate/whatever is no longer acting as a base. That, plus it's ionic and therefore no longer soluble.
A base is just an electron donor/proton acceptor in a reaction. A base does not depend on existance of water, although usually it is used in that context. And just because it's not in a solution doesn't mean it won't react. The sulfuric and hydrofluoric acid molecules are still very mobile and will react with solid bases, they just have to come into contact. Pour some 98% sulfuric acid onto solid sodium hydroxide, trust me, you'll get a violent acid-base reaction.
If the water is supercritical, would it instead be Hydrogen Flouride and not Hydroflouric acid? Of course as soon as the water returns to being subcritical it would become hydroflouric acid.
fascinating, but classically tragic example of science journalism that shows the lab solution to a problem in society. can it be scaled? how many treatment plants? who makes the parts? is the funding allocated? expecting at least four more videos about plastic recycling before I hear the answers.
10 minutes of chemistry geekiness, and you end by saying “It’s not practical.” If it were practical, everyone would be doing it and there wouldn’t be a problem with forever chemicals. So given my interest in chemistry is zero, this video was just a waste of my time.
You come on in front of the entire internet and admit that you spent 10 minutes of your life watching something you're not interested in and you think the problem is with someone else? Dunning Krueger club, party of you.
I didn't even notice that. I think unnecessary nitpicking of irrelevant minor clothing details is more unprofessional than that, frankly. Also kinda rude, and pointless.
1:32 Who's a good boy? 🦮 Oh no, the doggo is leaving the room! 😭 Great video, learned a lot from this, like that salt not being solvable in supercritical water is news to me and kinda make sense... unless the salt ions also become a gaseous at certain temperatures, maybe they rise to the top then, I dunno... 🤷 I think I also heard you hosting in an animated Ted-Ed video. Is this true or was that my imagination?
Supercritical fluids are useful for all kinds of stuff. For example, supercritical CO2 can remove caffeine from coffee without pulling out anything else. Check out our shorts content for more about that coming soon.
There are, I think hundreds, if not thousands, of similar compounds to the PFAS molecule shown on the white board. Companies are phasing some out, but are going to still produce others. This needs to be known about, and opposed. Different forever chems could be even worse.
The science and probably loads of applications behind it are really cool. Thanks for explaining.
However when it comes to solving the salted earth problem that is pfas, a new way of disposal is but a drop in the ocean.
If we can find a way to seperate all the insects from every part of dirt on this earth we'll be just a tiny step closer to actually getting the pfas out of the environment. And being able to destroy the part that really matters.
I like the honesty of this channel. A lot of science media over-hypes things for the clicks. This channel is pretty honest about the likelihood of these cool reactions becoming actual solutions to our problems.
It's a weird thing this channel. Google, American Chemical Society, and you will see they are actually a lobbying group for the chemical manufacturing industry. That though does come with a caveat, they hire ACTUAL chemists, and some of these chemists, get to do a TH-cam channel because it is good PR to educate. I think they get to do whatever they want really and it shows in the videos that they are actually having fun doing the science, so I have watched for years. Always good stuff and I like this guy especially because he knows a good gag.
To be fair, at 370+ degrees C and 200+ atmospheres of pressure, I too completely change my personality.
Extreme dissociative personality disorder
This is the only well researched videos about pfas i've seen on the internet so far. Even mentioned that firefighting foams are the main culprit and not pans. This video should have a lot more views.
Sign me up for super critical water cremation. I mean, not like right now. Gimme a few decades. I've still got stuff to do.
You might want to check out a more accessible and possible method called _aquamation._ This is a process where sodium hydroxide is used to reduce the body to material that can be safely flushed unto waterways like treated sewage is. (Probably even safer than sewage treatment.) Aquamation turns the body liquid.
I recommend looking up Caitlin Doughty of "Ask A Mortician" for more info.
I don't usually comment, but I have to say this is fantastic scicomm. Came for the PFAS, stayed because I learned so much about supercritical fluids. Loved the theater-style demo in the kitchen. Makes chemistry relatable!
Came for some hopefully good news about PFAS.
Was almkst overwelmed with highly entertaining presentation.
Thank you for your excellent efforts.
I'm in the U.S. Navy and I can tell you that PFAS and PFOSes are currently the bane of my existence.
I was warned about the extreme dangers of HF in electronics school. Our instructor had been a chemical safety officer at Intel. He knew about the OG bone hurting juice that is hydrofluoric acid.
Was he missing a finger? I knew a guy from back when I worked there that didn't follow safety protocol and accidentally exposed his finger to HF (back in the 90s) and didn't know until he woke up in the middle of the night with strong pain and ended up needing to get it removed later.
HF is no joke!
@nombi5456 No, but I think he knew the guy that happened to. The initial treatment is to put a calcium gel injection into your BONES, and there's nothing they can do to make it less painful. If that doesn't work, then amputation. If you get HF all over yourself, there's nothing that anyone can do.
@@kj_H65fYes! He was missing a toe too! He only showed that to his best friends though.
I love the part "I don't know what you want from me!!"
HF varies a lot in danger with water content. Dilute HF is used as a glass etching solution by artists without much trouble. Anhydrous HF is truly awful stuff to work with.
10:25 We may not have supercritical water cremation, but we still have regular water cremation lol
(Some states allow you to basically pressure cook a body with lye into goo, which uses way less energy than fire cremation, and technically you're compostable at the end of the process)
Yes! We talked about this briefly in our episode on corn tortillas (I promise it was actually kinda relevant)
th-cam.com/video/_LKe9hmXdvM/w-d-xo.html
@@ACSReactions "... Now we nixtamalize the body ..." 😸
I Sweden we have a recycling fee on bottles and cans.
Shouldn't be to difficult to have the same on pfas products.
The paper recycling from newspapers is debited when you buy the paper etc.
The only big issue I can see is to stop illegal exportation.
The threat of stuff like pcb is still fresh in most adults, shouldn't be too difficult to get something like that going.
Nice idea, but not quite aligned with reality I'm afraid. The main contamination sources so far have been insufficiently regulated industry (so whether that's still a problem depends on where you live) and firefighting foams. Which is a problem because since there are no viable alternatives at the moment, you have to decide between contaminating the ground vs. letting people die. Not a choice I want to have to make.
Household contamination is also an issue, but mostly comes from waste water from washing textiles, so incineration is obviously not an option. The concentrations are so low that until a few years ago, we weren't even able to reliably measure it, let alone clean it up. And for incinerated solid wastes, if i recall correctly the main problem isn't air pollution but waste ash being used in fertilizing products.
There is no pretty solution. No pfas means people die and essential tech stops working, but in return we contaminate the environment. Imo the only reasonable thing we can do right now except do more research is avoiding unnecessary sources of contamination like waterproofed textiles.
While HF is certainly scary as is, you hit it on the nose at the end, a little cheap base like NaOH for example and you have NaF (toothpaste fluoride) and Na2SO4 (food additive). Also Both H2SO4 and HF are industrial valuable chemicals. It might be worth finding ways to recycle them back out of the process but probably easier to just have a base-adding second phase.
BTW, if you think those are scary, go look up ClF3 and FOOF. They make HF look like a cuddly kitten..
Just came looking to see if someone had mentioned those two. 😸
"... and saw that concrete floor of the vehicle assembly building was on fire..."
@@squidwardfromua What's that a quote from? 😸
@@Ice_Karma : I'd assume "Ignition!: An Informal History of Liquid Rocket Propellants" by John Clark. It is an excellent book that is full of stories containing sentences like that.
@@BrooksMoses An excellent idea, and the origin of one of my favourite phrases ("engine-rich exhaust"), but I just checked my full text-searchable electronic copy of it, and, alas, it doesn't contain the phrase "vehicle assembly building", and the only match for "concrete floor" is unrelated. Thanks for the suggestion, though. 😻
One of my favorite uses of supercritical water is supercritical water oxidation for power production. Basically you pump oxygen and fuel into your supercritical water reactor and it becomes an internal combustion steam engine.
It's very hard to do and the power output is limited by the amount of input energy you need to get it running. But it means that you can in theory create an engine that can use anything organic as a fuel source - wet biomass, dry biomass, factory waste, sewage.
So instead of a Mr. Fusion, you get a Mr. Combustion?
"... wet biomass, dry biomass, factory waste, sewage"
And PFAS right? 😁
Very interesting, the absorption would absolutely help concentrate the majority of the pollutants into a liquid slurry I’d imagine? This could be very helpful in my work with mycoremediation, or fungal bio degradation. Fungi possess the unique ability to break down forever chemicals. These are mainly white rot fungi that can do this, due to their ability to break down large chain carbon molecules like lignin. They employ the same techniques and methods to break down the PFAS emitting peroxides, ligases, etc.
4:30 I just tried to clean that smudge off my screen but it turned out to be super critical fluid all along...
Just found out about supercritical water remediation while researching exactly how bad the foam we still use is, and how hard l should be pushing them to switch to something else. I was glad to see that there is a scalable process for breaking this junk down, because there is so much of it. So much. There's a few thousand gallons at my facility alone, and enough has been flowed at the training center that the ground suds when it rains.
This legitimately sounds like the job for one of those modular micro reactors as you could generate a lot of energy in a remote location for public safety. Maybe a Micro reactor manufacture could donate one of their products as a tax write off and as a test bed? If you made the acids available for free companies would be lining up to talk it off your hands the way it's done with used cooking oil, road millings, and scrap metal. Then it's no longer a waste issue but a logistics problem. Perhaps you would build this PFAS disposable facility where they would have otherwise produced the acids?
SCWO is definitely a good way to go about dealing with PFAS, especially with surrounding COD to drive it.
Look into HALT, EO, plasma treatment, and UV activated advanced oxidation techniques if you want to look at things even more creative
What is "COD"?
I work in the industry and you did a great job!
Concentration is another parameter that affects the choose of treatment method,
ppt, ppb and ppm level are more difficult to treat than that of high concentrated solution.
My friend plays tennis next to a car detailing plant, she asked me what was in this 4 gallon drum. I came to have a look, it contained aqueous hydrofluoric acid. It was on private property, not much could be done, it wasn't leaking or anything. It dissolves oil and grease (amongst other things) and is good at cleaning cars.
Can someone elaborate why supercritical water is a non-polar solvent? The only thing I can think of is this being due to very rapid rearrangement of the molecules and hence, averaging out the dipole moment? If true, does this general concept apply to (mostly) all supercritical fluids, do they all act as if non-polar?
We really wanted to include that in the video, but haven't been able to find a good explanation for this. We've come up with several hypotheses, but wouldn't want to just speculate in the comments. Let us know if you find any info!
Yeah, that's a good question. I don't think it is known for certain just yet why that is.
I wondered if the pressures involved might be able to overcome the forces involved that dictate the bond angle. Apparently this is wrong. Very wrong; Its not even close. The forces involved in maintaining the bond angle are great.
One of the more straightforward and simple theories put forth has to do with the expected (calculated, estimated) value of one of water's properties to be at those temperature and pressure regimes.
And that property is water's _dielectric constant_, or the ratio of its electric permittivity to the electric permittivity of a vacuum, also called simply the "relative permittivity". Permittivity is a property that affects the Coulomb force, or the electrostatic force of either attraction or repulsion between two point charges. It is the Coulomb forces of water's hydrogens and oxygen, along with its bond angle, which introduces an asymmetry in the molecule, which is responsible for its polarity.
ANYWAYS, water has been tested over a wide range of pressures and temperatures.
"Ah, so the relative permittivity must decrease with temperature and decrease with pressure," I thought.
I thought wrong.
Water has been found to:
decrease relative permittivity with increasing temperature
INCREASE relative permittivity with increasing density
...so that means the relative permittivity stays about the same, right? ... RIGHT!?
Again, I was wrong.
There is a large region in which water is considered supercritical, but the supercritical region being considered here, both in the video and in discussions of this effect is in the regions of very high pressure only (while the temperature may be somewhat more variable).
And it is within this region that water is calculated (I don't think it has been directly measured, as that could be somewhat difficult--although I could be wrong) to have a relative permittivity in the range of 10 to 25.
By comparison, water as we are used to encountering it (room temperature at 1 atm) has a relative permittivity of 80.
Values of 10 to 25 are similar to those of dipolar liquids, such as acetone or ethanol, under ordinary conditions.
And this, seemingly, explains it... EXCEPT THAT'S WRO--Naw, I'm just fooling about. This does indeed conclude the explanation, according to the hypothesis.
it's still polar (form what i've found), but as said in the video, it's acting in between a gas and a liquid. I think than when water molecules have a ton of speed (because of the high temperature) they cant rearrange around an ion to dissolve it as they do in liquid state, they go too fast and the water solvation sphere simply breaks.
The reason because they dissolve non polar molecules i think it's the same reason, it's acting like a gas. The molecules go so fast that the non polar molecules are kicked of and dispersed in the fluid.
I could just look this up, but 1) How are we going to isolate PFAS to a high enough purity to not cause other reaction issues and unwanted by products? And 2) if we can separate it, isn't there some way of recycling it into more or different PFAS materials? Eg: why can't fire fighting foam just be a soup of reused PFAS and viscosity-controlling agents and such? 3) Why don't we just use the HF as a chemical feedstock, since we have to mine fluorite and mix it with sulfuric acid to make HF anyway?
Great video! And I love the cute dog in the background :D
Damn, now I want to be super critical water cremated when I die.
just wanna say your videos are so good and i learn something new i've never heard before everytime - and i subscribe to lots of science channels too!
Agreed and their is a practical solution to capture both HF and sulfuric and sulfurous acid from the super critical oxidation reaction it’s being used today to control the waste pyrolysis of fluoridated coatings over medical and carpet treatments and called Alterin technology and used in the UK today trough upcycling global
Super well-explained video, first time seeing this channel, and loved it!
Hmm does it have to be water tho? I mean, supercritical Xenon seems to be quite easy to procure. Would it not do the trick? Or some other substance perhaps?
1:33 suuupppeeeerr cute! where is this dog going? its living the gud life !
I appreciate the possibility but it's too late for me... I don't think this reaction is going to get rid of the PFAS in my body.
Also, who's going to pay for it? Dupont may have made a killing on selling it but I have a feeling it will cost even more to get rid of it.
3M has already announced they're going to completely end PFAS production by 2025, so that's a good start.
Your dog seems to find your voice so comforting so much that it falls asleep.
Also, when you introduce bases, what kinds of molecules end up containing the fluorine?
I’ve been so fascinated with supercritical fluids since first learning about them. Very surreal. I never knew water’s properties changed so dramatically when supercritical.
I also find the bathtub in the basement quite curious. 🤔
Don't worry, they're just making soap. /j
Could be a dog bath.
A full bathroom in the basement usually means the basement was used as a separate apartment at some point - for a granny flat or for a boarder.
Great video, but in what world is C-F bond the 'strongest in organic chemistry'? I'm sure fx C=N would have significantly higher bond enthalpy
CF is the strongest natural single bond with carbon. CN is stronger but with two bonds. If you take per bond it would be lower. Still B-F, Si-F and H-F are stronger... all Fluor based though.
The strongest single bond with carbon, to be more precise with our language.
Super informative and very well presented!
Thank you!!!
How does it compare energy wise to destroying these chemicals using plasma?
Also, sCO2 will dissolve fats and oils. Can I use it to make the perfect (low fat) chip?
My new metal band name:
_Supercritical Water Cremation_
[grimaces musically]
Wonder where those forever chemicals came from. Hmmm...
This process needs more recognition
it's used industrially
@@thekaxmax I'm speaking about general use
@@KaushikAdhikari yes. I'm saying it already has recognition.
There are people working on getting it for smaller installations, as he said. But it's not there yet.
@thekaxmax I got it ! Hopefully it'll be available for general use sooner rather than later
How do we deal with the remaining PFAS? Can it be 100% destroyed? If not, how is it removed from the super-critical water after the reaction?
Good question. I think what you’d do is do multiple passes or extend the reaction time until you have something like 99.999% destruction.
@@ACSReactions That's still 10 ppm, though -- what is/are the acceptable limit/s for PFAS concentrations?
I breathed in, drank, and likely ate, PFAS from the DuPont Teflon plant in Washington, Ohio. Thank you, DuPont.
Oxidation by supercritical water releases Hydrofluoric acid which could be neutralized by lime, calcium hydroxide.
But the real problem is to extract the PFAS from waste water so as not to have too large volumes to treat.
Extraction would logically be possible with a perfluorinated polymer absorbent.
Now that some states have established maximum PFAS concentrations allowed in drinking water, I hope affordable technology exists to remove it from municipal water systems.
HF has the acidity of citric acid (lemon juice) so the acidity isn't the real problem. The problem is that it's a molecule so little that can go throught gloves and skin easly, and when it's in the body it bonds strongly to the calcium in your organism and therefore can't be used for muscle function, leading to a cardiac arrest and death.
@0:35 wait, the way you say this makes it sound like a very specific thing that only happens to a select group of elements/molecules. I thought everything could be a superfluid so long as it doesn't decompose under the conditions. (Whether we can produce the conditions is the question). But I can't think of an element that can't do it , in theory, and the same for most simple molecules too.
Also @0:45 that must be the world's least powerful gas burner on the left behind him, seeing as how it burns at less than 374°C.
9:43 what alchemy is this! please teach me these ways so that i can add this fizz to my beer (and wine?)
where this process is made? If it's made in a metal container. does the supercritical water corrodes the metal and produces H2 that leaks throught the metal and weekens it?
I wonder how one would extract the PFAS from whatever it is bonded to. I don't think they want to put frying pans into the reactor
Question: if PFAS is in everything and everyone, how do we safely extract and collect it in order to oxidize it this way?
L'oxydation par l'eau super critique libère de l'acide Fluorhydrique qui pourrait être neutralisée par de la chaux, calcium hydroxyde.
Mais le vrai problème est d'extraire le PFAS des eaux réiduaire afin de n'avoir pas de trop grands volumes a traiter.
L'extraction serait logiquement possible avec un absorbant polymère perfluoré.
How do you make PFAS?
Can CO2 on its supercritical phase serve similar purpose with less drastic pressure and temperature parameters?
Thanks for the video, you're doing excellent job ❤
Supercritical CO2 isn't useful for oxidizing PFAS, but it can selectively remove caffeine from coffee. We have a short coming about this in the not-too-distant future, stay tuned.
Supercritical CO2 is basically just dry cleaning.
@@ACSReactions It can also be used to make THC concentrates without using flammable and/or explosive solvents like butane.
what we need to do to keep these chemicals out of our tables?
could supercritical water be used for destroying nuclear waste from nuclear power plants?
So water is clearly just showing off at this point.
Water has already won the award for the #1 most dynamic, useful, diverse and amazing chemical compound of all time, and in two award categories: Solvents, general and chemical compounds essential for life. Or at least it is in my book, anyways.
Water could have easily retired once the 10th phase of water ice was found. And yet, they are up to, what, 18 now? 19? What a total powerhouse!
Water just loves flexing on the competition, I guess.
I once said that if I was the competition, I would want to cry, until someone pointed out to me: "Cry what?" BAH! Yet another W for water, that jerk!
Fluorine compounds... Run also amazing video didn't know that property of water at those states
Super-critical water cremation sounds like a fine idea except for the high energy costs and encouraging a commercial process involving high pressures to go into a sector that's not accustomed to them.
Fire cremation requires an absurd amount of energy and generates a lot of CO2 because, well, burning, and also tends to emit a shocking amount of mercury, because of fillings. Super-critical water cremation avoids a lot of that, but replaces it with straight up energy costs and a pressure vessel just desperate to have a BLEVE
There is lots of energy to do this, you can set up a solar oven and literally burn PFAS while the sun shines.
Lost me in saying industry doesn't like SO4 and HF. HF may not be as common, but they're still frequently used. So what's the issue with recovering the acids to sell back to industry?
The issue is that they’re corrosive/reactive, so you don’t want them destroying the expensive equipment you built
@@ACSReactions Oh, ok. Seems like an obvious engineering issue, one we've already solved at least partly, making your statement a little, well....... I mean, sure, we're able to produce bottles of fluoroantimonic acid, and while containers may not be at extreme pressures or temperatures, we've still figured out how to ship it around the world safely. According to the molecular electricians I know, FAA is much scarier than HF and SO4. If only it were a matter of lateral thinking finding lining substances inert or resistant to the conditions present, could be made cheaply sacrificial, or electrifying the device to control corrosion somehow..... Nah. That's silly. Defeatism for the......win?
Supercritical water does not hold salts. Wonder if it would be worth it converting salt water to fresh at extreme depths and then using the flow of fresh water to power the process. Probably not but it is a thought.
i feel like if they went to the people that build nuclear powerplants they could get there costs down lots of high pressure water runs through nuclear plants and im willing to bet it can handle the preasures and temps they would need to hit bonus points if they use it in a cooling loop for an actual reactor but i wouldn't considering how corrosive the reaction would be over time to heating system i would be suprised if it could last more then 10 years before the entire thing needs to be replaced
His goldie is often in the background, sleeping 💤. His interest in chemistry, or lack thereof, is evident.
Wait wait wait.
If water behaves like a non-polar molecule when it's supercritical, does that imply that its polar character is only because of autoionization?
That sounds silly because it would imply that water autoionizes even as a subcritical gas but what explains the non-polar behavior at supercritical temperatures and pressures?
Does the bond angle change? I suppose water would be expressing its vibrational modes at such temperatures but is it because the sawhorse (sp3 hybridized oxygen) is able to flip the hydrogens about its center plane (dividing the hydrogens and electron pairs) at a high enough frequency such that it's approximately linear?
That sounds much more plausible than an autoionizing gas.
I suppose by that logic, if oxygen is rotating fast enough about 1 of the 3 primary axes, it would also look non-polar.
Woah. Surely there's literature on that. Anyone have a good reference?
What does it even *mean* to be a "base" in supercritical water? Water dissociating into ions is the entire basis of pH, if thats not happening any more then your sodium hydroxide/bicarbonate/whatever is no longer acting as a base. That, plus it's ionic and therefore no longer soluble.
A base is just an electron donor/proton acceptor in a reaction. A base does not depend on existance of water, although usually it is used in that context.
And just because it's not in a solution doesn't mean it won't react. The sulfuric and hydrofluoric acid molecules are still very mobile and will react with solid bases, they just have to come into contact.
Pour some 98% sulfuric acid onto solid sodium hydroxide, trust me, you'll get a violent acid-base reaction.
When there's a long lineup in the bathroom behind me I always try to PFASt
If the water is supercritical, would it instead be Hydrogen Flouride and not Hydroflouric acid? Of course as soon as the water returns to being subcritical it would become hydroflouric acid.
Billion-dollar cleanup of PFAS contamination at military bases.
Sounds like you could clean the entire ecosystem with just a few nuclear reactors
Make my FAS the PFAS, I want my FAS FASSED Up!
(My apologies to Parliament Funkadelic)
0:01 i think i just saw one of them decay! :+D ...
Why is cremation using supercritical water a bad idea? Seriously.
fascinating, but classically tragic example of science journalism that shows the lab solution to a problem in society. can it be scaled? how many treatment plants? who makes the parts? is the funding allocated? expecting at least four more videos about plastic recycling before I hear the answers.
Sometimes I have to pee fast
4:23
you should have not do that blur thingy that was on a screen for 5 minutes straight, pretty innerving 😄
make bupont pay 4 it
"Liquid Water" ARGH! ARGH! ARGH! You made a funny!
just stick the barrels of fire fighting foam into the same mountain caverns that the nuclear waste gets stored in
DOG
I was wondering how a channel about chemical reactions was going to talk about PFAS, something very nonreactive.
PFAS, not possible w/out chemical reactions. Please make sure brain is in gear before dumping the clutch on your mouth.
hmm, sounds expensive. let's just keep dumping waste into the ground or yeeting it into the ocean
Just microwave the water. You can get it super critical haha
Superheated, not supercritical.
Fourth state of matter is plasma, not supercritical fluid.
10 minutes of chemistry geekiness, and you end by saying “It’s not practical.” If it were practical, everyone would be doing it and there wouldn’t be a problem with forever chemicals. So given my interest in chemistry is zero, this video was just a waste of my time.
You come on in front of the entire internet and admit that you spent 10 minutes of your life watching something you're not interested in and you think the problem is with someone else? Dunning Krueger club, party of you.
Thank you for wearing a better belt, but your boxers were still visible (at least not as much as before)...its distracting and unprofessional.
I didn't even notice that.
I think unnecessary nitpicking of irrelevant minor clothing details is more unprofessional than that, frankly. Also kinda rude, and pointless.
@@IstasPumaNevadarudely irrelevant pretty much describes his entire life, I'm willing to bet.
10:12 Chemical weapons actually can be incinerated. en.wikipedia.org/wiki/Tooele_Chemical_Agent_Disposal_Facility
1:32 Who's a good boy? 🦮 Oh no, the doggo is leaving the room! 😭
Great video, learned a lot from this, like that salt not being solvable in supercritical water is news to me and kinda make sense... unless the salt ions also become a gaseous at certain temperatures, maybe they rise to the top then, I dunno... 🤷
I think I also heard you hosting in an animated Ted-Ed video. Is this true or was that my imagination?