16 ms·

Simple mix of soap and solvent could help destroy ‘forever chemicals’

213 points by ckcheng 4y ago

ckcheng 4y ago
> What’s left behind, Trang says, is mostly easily captured fluorine ions, and a mixture of harmless, naturally occurring carbon and oxygen containing byproducts, her team reports today in Science. > Roughly 40% of PFAS compounds contain carboxylic acid groups, and thus could potentially be degraded by the new approach, Trang says. Though it has yet to be tested in the field, she adds that the most likely strategy would be to use conventional means to filter PFAS chemicals from, say drinking water, and then treat them off-site. > The method doesn’t work on all types of PFAS, however. Compounds used in flame retardants and batteries, for example, contain a sulfonate group instead of a carboxylic acid group and won’t break down with this approach.
- daniel-cussen 4y ago
  Batteries contain PFAS? Now I gotta test everything.
  - birdyrooster 4y ago
    PFAS seems to be used in keeping water out, so that makes sense. I suppose we might be able to find PFAS anywhere products are exposed to water with negative consequences.
- deleted 4y ago
  [deleted]
culi 4y ago
Now that Teflon got sued and switched to a different, probably more harmful, chemical I wonder if we'll want to go back to the OG "forever chemicals"
- Teknoman117 4y ago
  That's honestly one of the things I wish we could get a handle on. Company gets sued for using and hiding the danger of a compound they learned fairly quickly was toxic. Goes and invents another compound and switches to it without having to prove its safety. After it becoming public that they were intentionally hiding dangers for a half century, I feel we should take away their ability to be given the benefit of the doubt. All I think they learn from these lawsuits is that they need to get better at identifying and removing people who will call them out on their bullshit. Edit - I know the whole thing with DuPont was using PFOAs in the manufacturing process and leaking (intentionally dumping) them into the environment, but it's not like the final product (Teflon) is safe to ingest either, which as a cooking surface, you most definitely will in some quantity.
  - ars 4y ago
    > but it's not like the final product (Teflon) is safe to ingest either Sure it is. I don't think a less toxic material than Teflon even exists. It's toxicity is comparable to water. The LD50 of Teflon is > 11,280 mg/kg. Water by comparison is 90,000 mg/kg. They were not able to measure the exact toxicity because it's impossible to eat so much.
    - deleted 4y ago
      [deleted]
    - Dan_- 4y ago
      Bullshit. There is “toxic” and there is “causes cancer, even outside California, reduces fertility, and negatively affects fetal development.” Just because something doesn’t kill you immediately does not mean it isn’t harmful.
      - ars 4y ago
        Teflon is not harmful. Period. It doesn't cause ANYTHING in the body. It's about the most inert material that you can possibly ingest.
sbierwagen 4y ago
The paper: https://www.science.org/doi/10.1126/science.abm8868 https://www.science.org/doi/10.1126/science.abm8868 The "soap and solvent" is sodium hydroxide (lye) and DMSO at 120 degC. Those are... fairly... well behaved chemicals, but lye is stout stuff and DMSO attacks nitrile gloves. You could imagine a remediation process that uses this process but the combo ain't exactly Dawn dish soap. I'd almost prefer pyroprocessing over it.
- chasil 4y ago
  DMSO is not well-behaved. It easily penetrates human skin, and carries solutes with it. Don't touch! "DMSO can cause contaminants, toxins, and medicines to be absorbed through the skin, which may cause unexpected effects. "Because DMSO easily penetrates the skin, substances dissolved in DMSO may be quickly absorbed. Glove selection is important when working with DMSO. Butyl rubber, fluoroelastomer, neoprene, or thick (15 mil / 0.4 mm) latex gloves are recommended. Nitrile gloves, which are very commonly used in chemical laboratories, may protect from brief contact but have been found to degrade rapidly with exposure to DMSO." https://en.m.wikipedia.org/wiki/Dimethyl_sulfoxide https://en.m.wikipedia.org/wiki/Dimethyl_sulfoxide
  - biotinker 4y ago
    That's true, but in and of itself, it's less toxic to humans than ethanol is. It degrades in the environment quite readily, as well. If we were looking for a chemical to deploy at scale to clean up PFAS in existing environments, we could do much worse.
    - bergenty 4y ago
      It’s a carrier. It introduces whatever is in it to your bloodstream.
      - nfhshy68 4y ago
        Does it release it?
samwillis 4y ago
Slightly off topic, I’m keen to dispose of our Teflon frying pan. Does anyone have a good recommendation for an alternative, ideally one that doesn’t take too much “maintenance”? We also have a Teflon milk pan but that is never used at a high tempriture so I’m less concerned about that.
- droopyEyelids 4y ago
  You could get a new pan with 'ceramic' coating. It's just like teflon in basically every way.
  - ok_dad 4y ago
    > It's just like teflon in basically every way. Hopefully not in the bad ways? Is the "ceramic coating" proven to not be harmful?
    - ars 4y ago
      What bad ways? Teflon is not harmful. Teflon is not the same as PFAS, and Teflon cookware does not leech any PFAS into food. See my other reply: https://news.ycombinator.com/item?id=32515717 https://news.ycombinator.com/item?id=32515717 And to answer your question, ceramics sometimes have heavy metals to get bright colors (cadmium mostly). Make sure to buy from a reputable manufacturer.
      - radicalbyte 4y ago
        My Teflon pans are all slightly scratched. When they scratch some material comes loose and is removed from the pan. Where is that material?
        ars 4y ago
        You ate it, and it won't hurt you in the slightest. Teflon is utterly inert in the body.
      - 4y ago
superkuh 4y ago
I was excited for a moment but PFOS (Perfluorooctanesulfonic acid, a PFAS) doesn't have a carboxyl group so I guess Minnesota's (US state) 3M polluted waters won't get any respite.
- DoingIsLearning 4y ago
  FYI not a US only issue. Same 3M contamination of groundwater happened in Belgium (Zwijndrecht plant) and the Netherlands (Dordrecht plant), with very little international coverage.
smm11 4y ago
DMSO and soap is expensive? Okay, then.
- _carbyau_ 4y ago
  I was more worried about heating it all up to 120C. I mean, how is that going to work in any practical sense?
kortex 4y ago
> Computer calculations by colleagues at the University of California, Los Angeles, revealed DMSO knocks off the carboxylic acid group. “Once that happens it causes the entire molecule to fall apart in a cascade of reactions,” Dichtel says. Big if true. I'm slightly skeptical that just decarboxylating PFAS causes the rest of the backbone to "fall apart" - I would expect it to form CF3[CF2]· (carbon radical) which would readily react with water to form -H or -OH, which is basically back to square one. But maybe it can eliminate HF in the presence of UV, forming CF3[CH2]CF=CFOH, which gets hydrolyzed, oxidized, then cleaved, but boy is that an unfavorable process. (edit: skimmed the paper, I was pretty close. Forms CF3[CF2]- which goes to CF3[CH2]CF=CF2 which then gets hydrolyzed, but...DMSO/NaOH at 80-120°C ...yikes. This is the ochem equivalent of "nuke the site from orbit", very few compounds survive these conditions) I've been out of the chemistry game for a few years now so I'm a bit rusty but gut instinct is that this is far from a slam dunk. But anything to reduce FC's is a boon to the world, so I'm hopeful this is a breakthrough. Edit2: > This high fluoride recovery indicates that most of the perfluoroalkyl fluorines were defluorinated and mineralized rather than being transformed to smaller-chain PFAS or being lost as volatile fluorocarbons. So the surprising thing isn't the decarboxylation, it's that NaOH encourages the perflourylalkenes to cleave at sites away from the alpha (splitting, rather than carbon-by-carbon), which is neat. Still doesn't touch PFOS, unfortunately.
kragen 4y ago
Headline is a lie: as we finally find out halfway through the article, it's not soap but lye, sodium hydroxide. The solvent is the fairly nontoxic dimethyl sulfoxide, so both of these are safe to release into the environment. In https://news.ycombinator.com/item?id=32515659 https://news.ycombinator.com/item?id=32515659 sbierwagen reports that the reaction requires 120-degree temperatures so this isn't suitable for in-situ remediation.
- fnordpiglet 4y ago
  Well if we coat the earth in lye global warming will take care of the rest. Problem solved.
- rad88 4y ago
  The reaction doesn't "require" 120C, that was simply the first experiment they described. They began by confirming that this reaction actually takes place and discovering which PFAs were neutralized by it. To that end they boiled a mixture of the stuff for 24 hours. The reaction can occur at more moderate temperatures. There is more analysis (with experimental results) further down in the paper: > Substantial defluorination still occurred when the isolated PFOA degradation product (perfluoro-1H-heptane 2) was subjected to degradation conditions but heated to only 40°C (table S3).
  - kragen 4y ago
    Okay, but you can't, for example, heat up large masses of contaminated dirt to 40° without killing everything in them. And you probably can't even saturate them with DMSO, both because even though it's relatively nontoxic it's not that nontoxic, and because it's expensive.
    - rad88 4y ago
      I was (totally) wrong, but can't delete or edit the comment.
      - kragen 4y ago
rob_c 4y ago
Surely the label "forever chemicals" was a bit alarmist if household cleaning goods could break them down...
- ceejayoz 4y ago
  They're "forever" because they persist in the environment. You're not likely to find this specific combination of temperature and solvents in the wild. It's something you might be able to use in water treatment plants in areas where the supply has been contaminated. As the article notes, we already had ways of breaking them down, just with difficultly: "current PFAS-destruction techniques, such as incineration, can require vast amounts of energy, superhigh temperatures, and millions of dollars".
  - rob_c 4y ago
    So cleaning up after ourselves as a species requires effort... Again, this... Frankly doesn't surprise me, and I'm not blaming you for posting it but it just makes me want to crawl back into a cave and watch it all burn...
- freemint 4y ago
  The same household chemicals (especially at 120 degrees C) would kill all life. They are effectively forever in the environment.
  - cityofdelusion 4y ago
    Well, on human timescales, yes. They will eventually subduct into the mantle and be vaporized.
  - rob_c 4y ago
    Yes, extracting contaminated materials from an environment and decontaminating them would removing life because it's destructive. That's what cleaning this stuff up involves. I'm all for "environmentally damaging" or someother name but "forever chemicals" is just a bad name for this that is going to get picked up on by people. I'm not suggesting burn so much co2 that the planet gets to 120C, although it'd have less human problems at that point.
alliao 4y ago
we're littering the planet so bad quite overwhelming whenever I try to think about it
pueblito 4y ago
On the topic of PFAS, I’ve used a https://www.berkeyfilters.com/ https://www.berkeyfilters.com/ for 10+ years and they filter out PFOS PFAS etc
- armitron 4y ago
  Berkey filters look like a scam to me: https://archive.ph/ixmXD https://archive.ph/ixmXD The fact that they refuse to get certified / conduct any independent rigorous testing (like in NSF/ANSI certification) should have clued you in. "We also cut open a pair of Black Berkey filters to see how they are constructed and to look for evidence that, as Berkey marketing claims, they contain “at least” six different filtering elements. We found that though the Berkey filters are larger and denser than filters from Brita and 3M Filtrete, they appear to share their filtration mechanisms: activated charcoal impregnated with an ion-exchange resin. " I wouldn't count on any of this to filter chemicals, much less PFAS.
  - kragen 4y ago
    Ion-exchange resins are fantastic at filtering some chemicals though.
fnordpiglet 4y ago
Great now we just need to coat the earth in lye
pressurefree 4y ago
jokoon 4y ago
I haven't heard a lot of those forever chemicals in the news lately, I wonder why.
- eesmith 4y ago
  What news sources do you read? A search across the last 6 months at HN - https://hn.algolia.com/?dateRange=pastYear&page=0&prefix=false&query=forever%20chemicals&sort=byDate&type=story https://hn.algolia.com/?dateRange=pastYear&page=0&prefix=fal... - shows: > Pollution: 'Forever chemicals' in rainwater exceed safe levels(https://www.bbc.com/news/science-environment-62391069 https://www.bbc.com/news/science-environment-62391069) 12 days ago > Forever Chemicals PFAS, PFOA, PFOS, BPA, Explained Clearly [video](https://www.youtube.com/watch?v=8QuvTjLZaXs https://www.youtube.com/watch?v=8QuvTjLZaXs) 2 months ago > 3M’s PFAS Crisis Has Come to Europe(https://www.bloomberg.com/graphics/2022-3m-pfas-toxic-forever-chemicals-europe https://www.bloomberg.com/graphics/2022-3m-pfas-toxic-foreve...) 2 months ago > EPA: 'Forever chemicals' pose risk even at low levels(https://apnews.com/article/science-climate-and-environment-government-politics-1997041096d6fc84edde97cf16f72bce https://apnews.com/article/science-climate-and-environment-g...) 2 months ago > PFAS chemicals do not last forever [i.e. PFAS can be destroyed](https://phys.org/news/2022-05-pfas-chemicals.html https://phys.org/news/2022-05-pfas-chemicals.html) 3 months ago > PFAS Linked to Liver Damage(https://www.studyfinds.org/forever-chemicals-liver-damage/ https://www.studyfinds.org/forever-chemicals-liver-damage/) 4 months ago > Regular blood donations can reduce “forever chemicals” in the bloodstream: study(https://theswaddle.com/regular-blood-donations-can-reduce-toxic-forever-chemicals-in-the-bloodstream-study/ https://theswaddle.com/regular-blood-donations-can-reduce-to...) 4 months ago > Farewell, forever chemicals: Researchers aim to eliminate PFAS for good(https://phys.org/news/2022-03-farewell-chemicals-aim-pfas-good.html https://phys.org/news/2022-03-farewell-chemicals-aim-pfas-go...) 5 months ago > The farmers facing ruin in Maine’s ‘forever chemicals’ crisis(https://www.theguardian.com/environment/2022/mar/22/i-dont-know-how-well-survive-the-farmers-facing-ruin-in-americas-forever-chemicals-crisis https://www.theguardian.com/environment/2022/mar/22/i-dont-k...) 5 months ago > Michigan beef found to contain dangerous levels of ‘forever chemicals’(https://www.theguardian.com/environment/2022/feb/11/michigan-beef-dangerous-levels-forever-chemicals https://www.theguardian.com/environment/2022/feb/11/michigan...) 6 months ago
sivizius 4y ago
KOH is not soap, it is used in the production of soap and KOH will make your skin to soap. Destroying anything organic by cooking it in strong lye at 120 °C with quite polar solvent is not something unexpected. It might be optimised with crown ethers or other phase-transfer catalysts, but I cannot see how this is a milder treatment than simple heating it until decomposition. To make this reaction affordable one has to extract/purify these forever-chemicals first. Otherwise, mostly other stuff will be destroyed. Lime (Ca(OH)₂) is somewhat cheaper in this quantities, maybe this reaction can be done with it. This will also bind any fluoride ions, which would make this way less toxic.

213 points by ckcheng 4y ago

> What’s left behind, Trang says, is mostly easily captured fluorine ions, and a mixture of harmless, naturally occurring carbon and oxygen containing byproducts, her team reports today in Science. > Roughly 40% of PFAS compounds contain carboxylic acid groups, and thus could potentially be degraded by the new approach, Trang says. Though it has yet to be tested in the field, she adds that the most likely strategy would be to use conventional means to filter PFAS chemicals from, say drinking water, and then treat them off-site. > The method doesn’t work on all types of PFAS, however. Compounds used in flame retardants and batteries, for example, contain a sulfonate group instead of a carboxylic acid group and won’t break down with this approach.

daniel-cussen 4y ago
Batteries contain PFAS? Now I gotta test everything.
- birdyrooster 4y ago
  PFAS seems to be used in keeping water out, so that makes sense. I suppose we might be able to find PFAS anywhere products are exposed to water with negative consequences.
deleted 4y ago
[deleted]

culi 4y ago

Now that Teflon got sued and switched to a different, probably more harmful, chemical I wonder if we'll want to go back to the OG "forever chemicals"

Teknoman117 4y ago
That's honestly one of the things I wish we could get a handle on. Company gets sued for using and hiding the danger of a compound they learned fairly quickly was toxic. Goes and invents another compound and switches to it without having to prove its safety. After it becoming public that they were intentionally hiding dangers for a half century, I feel we should take away their ability to be given the benefit of the doubt. All I think they learn from these lawsuits is that they need to get better at identifying and removing people who will call them out on their bullshit. Edit - I know the whole thing with DuPont was using PFOAs in the manufacturing process and leaking (intentionally dumping) them into the environment, but it's not like the final product (Teflon) is safe to ingest either, which as a cooking surface, you most definitely will in some quantity.
- ars 4y ago
  > but it's not like the final product (Teflon) is safe to ingest either Sure it is. I don't think a less toxic material than Teflon even exists. It's toxicity is comparable to water. The LD50 of Teflon is > 11,280 mg/kg. Water by comparison is 90,000 mg/kg. They were not able to measure the exact toxicity because it's impossible to eat so much.
  - deleted 4y ago
    [deleted]
  - Dan_- 4y ago
    Bullshit. There is “toxic” and there is “causes cancer, even outside California, reduces fertility, and negatively affects fetal development.” Just because something doesn’t kill you immediately does not mean it isn’t harmful.
    - ars 4y ago
      Teflon is not harmful. Period. It doesn't cause ANYTHING in the body. It's about the most inert material that you can possibly ingest.

sbierwagen 4y ago

The paper: https://www.science.org/doi/10.1126/science.abm8868 https://www.science.org/doi/10.1126/science.abm8868 The "soap and solvent" is sodium hydroxide (lye) and DMSO at 120 degC. Those are... fairly... well behaved chemicals, but lye is stout stuff and DMSO attacks nitrile gloves. You could imagine a remediation process that uses this process but the combo ain't exactly Dawn dish soap. I'd almost prefer pyroprocessing over it.

chasil 4y ago
DMSO is not well-behaved. It easily penetrates human skin, and carries solutes with it. Don't touch! "DMSO can cause contaminants, toxins, and medicines to be absorbed through the skin, which may cause unexpected effects. "Because DMSO easily penetrates the skin, substances dissolved in DMSO may be quickly absorbed. Glove selection is important when working with DMSO. Butyl rubber, fluoroelastomer, neoprene, or thick (15 mil / 0.4 mm) latex gloves are recommended. Nitrile gloves, which are very commonly used in chemical laboratories, may protect from brief contact but have been found to degrade rapidly with exposure to DMSO." https://en.m.wikipedia.org/wiki/Dimethyl_sulfoxide https://en.m.wikipedia.org/wiki/Dimethyl_sulfoxide
- biotinker 4y ago
  That's true, but in and of itself, it's less toxic to humans than ethanol is. It degrades in the environment quite readily, as well. If we were looking for a chemical to deploy at scale to clean up PFAS in existing environments, we could do much worse.
  - bergenty 4y ago
    It’s a carrier. It introduces whatever is in it to your bloodstream.
    - nfhshy68 4y ago
      Does it release it?

samwillis 4y ago

Slightly off topic, I’m keen to dispose of our Teflon frying pan. Does anyone have a good recommendation for an alternative, ideally one that doesn’t take too much “maintenance”? We also have a Teflon milk pan but that is never used at a high tempriture so I’m less concerned about that.

droopyEyelids 4y ago
You could get a new pan with 'ceramic' coating. It's just like teflon in basically every way.
- ok_dad 4y ago
  > It's just like teflon in basically every way. Hopefully not in the bad ways? Is the "ceramic coating" proven to not be harmful?
  - ars 4y ago
    What bad ways? Teflon is not harmful. Teflon is not the same as PFAS, and Teflon cookware does not leech any PFAS into food. See my other reply: https://news.ycombinator.com/item?id=32515717 https://news.ycombinator.com/item?id=32515717 And to answer your question, ceramics sometimes have heavy metals to get bright colors (cadmium mostly). Make sure to buy from a reputable manufacturer.
    - radicalbyte 4y ago
      My Teflon pans are all slightly scratched. When they scratch some material comes loose and is removed from the pan. Where is that material?
      - ars 4y ago
        You ate it, and it won't hurt you in the slightest. Teflon is utterly inert in the body.
    - 4y ago

superkuh 4y ago

I was excited for a moment but PFOS (Perfluorooctanesulfonic acid, a PFAS) doesn't have a carboxyl group so I guess Minnesota's (US state) 3M polluted waters won't get any respite.

DoingIsLearning 4y ago
FYI not a US only issue. Same 3M contamination of groundwater happened in Belgium (Zwijndrecht plant) and the Netherlands (Dordrecht plant), with very little international coverage.

smm11 4y ago

DMSO and soap is expensive? Okay, then.

_carbyau_ 4y ago
I was more worried about heating it all up to 120C. I mean, how is that going to work in any practical sense?

kortex 4y ago

> Computer calculations by colleagues at the University of California, Los Angeles, revealed DMSO knocks off the carboxylic acid group. “Once that happens it causes the entire molecule to fall apart in a cascade of reactions,” Dichtel says. Big if true. I'm slightly skeptical that just decarboxylating PFAS causes the rest of the backbone to "fall apart" - I would expect it to form CF3[CF2]· (carbon radical) which would readily react with water to form -H or -OH, which is basically back to square one. But maybe it can eliminate HF in the presence of UV, forming CF3[CH2]CF=CFOH, which gets hydrolyzed, oxidized, then cleaved, but boy is that an unfavorable process. (edit: skimmed the paper, I was pretty close. Forms CF3[CF2]- which goes to CF3[CH2]CF=CF2 which then gets hydrolyzed, but...DMSO/NaOH at 80-120°C ...yikes. This is the ochem equivalent of "nuke the site from orbit", very few compounds survive these conditions) I've been out of the chemistry game for a few years now so I'm a bit rusty but gut instinct is that this is far from a slam dunk. But anything to reduce FC's is a boon to the world, so I'm hopeful this is a breakthrough. Edit2: > This high fluoride recovery indicates that most of the perfluoroalkyl fluorines were defluorinated and mineralized rather than being transformed to smaller-chain PFAS or being lost as volatile fluorocarbons. So the surprising thing isn't the decarboxylation, it's that NaOH encourages the perflourylalkenes to cleave at sites away from the alpha (splitting, rather than carbon-by-carbon), which is neat. Still doesn't touch PFOS, unfortunately.

kragen 4y ago

Headline is a lie: as we finally find out halfway through the article, it's not soap but lye, sodium hydroxide. The solvent is the fairly nontoxic dimethyl sulfoxide, so both of these are safe to release into the environment. In https://news.ycombinator.com/item?id=32515659 https://news.ycombinator.com/item?id=32515659 sbierwagen reports that the reaction requires 120-degree temperatures so this isn't suitable for in-situ remediation.

fnordpiglet 4y ago
Well if we coat the earth in lye global warming will take care of the rest. Problem solved.
rad88 4y ago
The reaction doesn't "require" 120C, that was simply the first experiment they described. They began by confirming that this reaction actually takes place and discovering which PFAs were neutralized by it. To that end they boiled a mixture of the stuff for 24 hours. The reaction can occur at more moderate temperatures. There is more analysis (with experimental results) further down in the paper: > Substantial defluorination still occurred when the isolated PFOA degradation product (perfluoro-1H-heptane 2) was subjected to degradation conditions but heated to only 40°C (table S3).
- kragen 4y ago
  Okay, but you can't, for example, heat up large masses of contaminated dirt to 40° without killing everything in them. And you probably can't even saturate them with DMSO, both because even though it's relatively nontoxic it's not that nontoxic, and because it's expensive.
  - rad88 4y ago
    I was (totally) wrong, but can't delete or edit the comment.
    - kragen 4y ago

rob_c 4y ago

Surely the label "forever chemicals" was a bit alarmist if household cleaning goods could break them down...

ceejayoz 4y ago
They're "forever" because they persist in the environment. You're not likely to find this specific combination of temperature and solvents in the wild. It's something you might be able to use in water treatment plants in areas where the supply has been contaminated. As the article notes, we already had ways of breaking them down, just with difficultly: "current PFAS-destruction techniques, such as incineration, can require vast amounts of energy, superhigh temperatures, and millions of dollars".
- rob_c 4y ago
  So cleaning up after ourselves as a species requires effort... Again, this... Frankly doesn't surprise me, and I'm not blaming you for posting it but it just makes me want to crawl back into a cave and watch it all burn...
freemint 4y ago
The same household chemicals (especially at 120 degrees C) would kill all life. They are effectively forever in the environment.
- cityofdelusion 4y ago
  Well, on human timescales, yes. They will eventually subduct into the mantle and be vaporized.
- rob_c 4y ago
  Yes, extracting contaminated materials from an environment and decontaminating them would removing life because it's destructive. That's what cleaning this stuff up involves. I'm all for "environmentally damaging" or someother name but "forever chemicals" is just a bad name for this that is going to get picked up on by people. I'm not suggesting burn so much co2 that the planet gets to 120C, although it'd have less human problems at that point.

alliao 4y ago

we're littering the planet so bad quite overwhelming whenever I try to think about it

pueblito 4y ago

On the topic of PFAS, I’ve used a https://www.berkeyfilters.com/ https://www.berkeyfilters.com/ for 10+ years and they filter out PFOS PFAS etc

armitron 4y ago
Berkey filters look like a scam to me: https://archive.ph/ixmXD https://archive.ph/ixmXD The fact that they refuse to get certified / conduct any independent rigorous testing (like in NSF/ANSI certification) should have clued you in. "We also cut open a pair of Black Berkey filters to see how they are constructed and to look for evidence that, as Berkey marketing claims, they contain “at least” six different filtering elements. We found that though the Berkey filters are larger and denser than filters from Brita and 3M Filtrete, they appear to share their filtration mechanisms: activated charcoal impregnated with an ion-exchange resin. " I wouldn't count on any of this to filter chemicals, much less PFAS.
- kragen 4y ago
  Ion-exchange resins are fantastic at filtering some chemicals though.

fnordpiglet 4y ago

Great now we just need to coat the earth in lye

pressurefree 4y ago

jokoon 4y ago

I haven't heard a lot of those forever chemicals in the news lately, I wonder why.

eesmith 4y ago
What news sources do you read? A search across the last 6 months at HN - https://hn.algolia.com/?dateRange=pastYear&page=0&prefix=false&query=forever%20chemicals&sort=byDate&type=story https://hn.algolia.com/?dateRange=pastYear&page=0&prefix=fal... - shows: > Pollution: 'Forever chemicals' in rainwater exceed safe levels(https://www.bbc.com/news/science-environment-62391069 https://www.bbc.com/news/science-environment-62391069) 12 days ago > Forever Chemicals PFAS, PFOA, PFOS, BPA, Explained Clearly [video](https://www.youtube.com/watch?v=8QuvTjLZaXs https://www.youtube.com/watch?v=8QuvTjLZaXs) 2 months ago > 3M’s PFAS Crisis Has Come to Europe(https://www.bloomberg.com/graphics/2022-3m-pfas-toxic-forever-chemicals-europe https://www.bloomberg.com/graphics/2022-3m-pfas-toxic-foreve...) 2 months ago > EPA: 'Forever chemicals' pose risk even at low levels(https://apnews.com/article/science-climate-and-environment-government-politics-1997041096d6fc84edde97cf16f72bce https://apnews.com/article/science-climate-and-environment-g...) 2 months ago > PFAS chemicals do not last forever [i.e. PFAS can be destroyed](https://phys.org/news/2022-05-pfas-chemicals.html https://phys.org/news/2022-05-pfas-chemicals.html) 3 months ago > PFAS Linked to Liver Damage(https://www.studyfinds.org/forever-chemicals-liver-damage/ https://www.studyfinds.org/forever-chemicals-liver-damage/) 4 months ago > Regular blood donations can reduce “forever chemicals” in the bloodstream: study(https://theswaddle.com/regular-blood-donations-can-reduce-toxic-forever-chemicals-in-the-bloodstream-study/ https://theswaddle.com/regular-blood-donations-can-reduce-to...) 4 months ago > Farewell, forever chemicals: Researchers aim to eliminate PFAS for good(https://phys.org/news/2022-03-farewell-chemicals-aim-pfas-good.html https://phys.org/news/2022-03-farewell-chemicals-aim-pfas-go...) 5 months ago > The farmers facing ruin in Maine’s ‘forever chemicals’ crisis(https://www.theguardian.com/environment/2022/mar/22/i-dont-know-how-well-survive-the-farmers-facing-ruin-in-americas-forever-chemicals-crisis https://www.theguardian.com/environment/2022/mar/22/i-dont-k...) 5 months ago > Michigan beef found to contain dangerous levels of ‘forever chemicals’(https://www.theguardian.com/environment/2022/feb/11/michigan-beef-dangerous-levels-forever-chemicals https://www.theguardian.com/environment/2022/feb/11/michigan...) 6 months ago

sivizius 4y ago

KOH is not soap, it is used in the production of soap and KOH will make your skin to soap. Destroying anything organic by cooking it in strong lye at 120 °C with quite polar solvent is not something unexpected. It might be optimised with crown ethers or other phase-transfer catalysts, but I cannot see how this is a milder treatment than simple heating it until decomposition. To make this reaction affordable one has to extract/purify these forever-chemicals first. Otherwise, mostly other stuff will be destroyed. Lime (Ca(OH)₂) is somewhat cheaper in this quantities, maybe this reaction can be done with it. This will also bind any fluoride ions, which would make this way less toxic.