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

science.org

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

#221

Post by rad88 »

kragen wrote: post #147
rad88 wrote: post #139

Earlier quoted context omitted.

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 defluor…

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.

I was (totally) wrong, but can't delete or edit the comment.

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

#222

Post by kragen »

rad88 wrote: post #221
kragen wrote: post #147

Earlier quoted context omitted.

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.

I was (totally) wrong, but can't delete or edit the comment.

Totally wrong how? Their mix doesn't break down perfluorinated stuff at 40 degrees?

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

#223

Post by kragen »

blix wrote: post #172
kragen wrote: post #170

Earlier quoted context omitted.

Silica gel is glass with nanometer-sized pores in it. Bottle glass has additional additives that lower its melting point and increase its solubility (oxides of sodium and calcium). The EU has irrationally banned all sorts of things since the witch-burners have seized control of the government apparatus. Borate fire retardants and fertilizers is one of my favorite examples.

Make some car windows out of silica gel and let me know how it goes :) I think you will find nanometer-sized pores can actually matter a lot! I'm not sure dismissing all research that disagrees with me as witch-burning would be a good habit as a scientist.

Nanometer-sized pores matter enormously, which is why we make silica gel in the first place, but not in ways that make other forms of amorphous silica more toxic than silica gel.

I'm not dismissing research that disagrees with me as witch-burning. I'm dismissing people who disagree with literally all the research.

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

#224

Post by kragen »

blix wrote: post #171
kragen wrote: post #169

Earlier quoted context omitted.

But the claim in question is one of the best-known and most thoroughly established claims in all of toxicology. Asking for scientific research supporting the biocompatibility of PTFE is akin to asking for scientific research supporting biological evolution or the claim that people have landed on the moon: it's a sure sign that the person making the demand has a pre-existing flimsy pretext for rejecting literally all…

If it's truly such a well established claim it should be trivial to find and link a study actually demonstrating its safety when ingesting small amounts over a large period of time. No such study was linked. Probably because longitudinal studies are extremely rare. It's not a rejection of all research to say that some questions remain unanswered. In fact, I'd say it is the foundation of good science to understand whi…

There are half a dozen studies per year, going back decades, assessing the safety of PTFE in implants. Many of them are longitudinal. Chemists routinely boil PTFE in acids such as hydrochloric and sulfuric for hours without degrading it even slightly; such degradation would contaminate their reactions.

I bet you can't find a study demonstrating natural selection in the split-leaf philodendron, either, but that isn't a good reason to go around saying "some questions remain unanswered" about whether the split-leaf philodendron is an exception to the laws of evolution.

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

#225

Post by kragen »

hedora wrote: post #184
kragen wrote: post #161

Earlier quoted context omitted.

How do you get it to be just above the smoke point of the oil without a thermostat or a suitable thermometer? The knob on my oven just varies the amount of gas going to the burner.

Oven thermometers are cheap, but barring that, use inexpensive canola or vegetable oil sparingly; just enough to make it shiny, and turn the knob to 350F (or whatever setting you use by default when baking or cooking). If the coating turns white, recoat with oil and try a lower temperature or less time. Cast iron is an extremely old technology, and was common back in the days of wood stoves. It doesn’t require precis…

Thanks! I'll give it a try.

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

#226

Post by kragen »

ars wrote: post #215
zardo wrote: post #200

Earlier quoted context omitted.

> This also isn't true. You can't heat your cookware above 500F / 260C, that's it. Which obviously no one does since everything would be burned black. People do badly burn their food and ruin their pans.

Yes, that's true, but if it were oil they would also kill their birds. Teflon is safer for birds than oil.

Not necessarily; if it were oil they would notice the smoke, while the fumes generated by teflon are quite subtle until a much higher temperature. So there have been many cases where people killed their birds before noticing that anything was wrong.

While I'm totally comfortable with eating teflon, I'm absentminded enough that I've overheated cookware many times, so I wouldn't use it if I had birds.

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

#227

Post by kragen »

armitron wrote: post #187
pueblito wrote: post #120

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

Berkey filters look like a scam to me: 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…

Ion-exchange resins are fantastic at filtering some chemicals though.

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

#228

Post by sbierwagen »

bell-cot wrote: post #199
chaxor wrote: post #149

Earlier quoted context omitted.

I think they meant well behaved in the sense that it isn't highly reactive - e.g. doesn't explode in contact with air. Not so much what it does to humans. We're talking about fluorine chemistry here, so things get kind of extreme.

"Extreme" is when you have elemental fluorine. Vs. nice, stable fluorine compounds & salts. This situation involves only the latter.

Well that's the problem, right? The more stable the substance you're trying to degrade, the more intense the conditions or chemicals you need. Teflon is inert as a rock, so if you for some reason needed to dissolve it in acid then you have to reach deep into the realm of impracticality and pull out demonic reagents like chlorine trifluoride or trihydridoboron.

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

#229

Post by namibj »

mellavora wrote: post #182
ngold wrote: post #38

Earlier quoted context omitted.

We just need to boil the world's oceans now

There was a concern that the hydrogen bomb would do that. Probably just a scare story.

It was briefly considered, then numbers run, and promptly determined that it wouldn't be possible (IIRC did to x-ray losses).

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

#230

Post by baby »

asdff wrote: post #107
baby wrote: post #61

Earlier quoted context omitted.

I’m not sure about general treatment, but one thing that you can’t do is let water sit in there, as it’ll rust.

If its super well seasoned it won't rust even with soaking for two days in dish soap.

I guess my brand new cast iron pans weren’t then
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