You Chemicals Features and What to Know

If you've used non-stick cookware recently or bought water-resistant clothes, you might have heard about PFAS, or "forever chemicals." We use PFAS in a lot of stuff. Non-stick coatings, stain repellents, waterproof fabrics, food packaging, even some kinds of firefighting foams… the list goes on and on. And there are thousands of different PFAS chemicals tailored to every possible need. We call them forever chemicals because they are super stable. That's partly by design. We want our raincoats and frying pans to do their jobs and last a long time. And we want our firefighting foams to…not immediately burn up in a fire.

The downside is that when we're done using those products, or fighting the fire, or even when manufacturers are making those things for us to use in the first place, the leftover PFAS don't just go away. It is very hard to break them down. They end up in landfills… and our soil and water. But it's not impossible to get rid of them. Scientists are coming up with a few ways to cut through that rock-solid stability and put an expiration date on forever.

[♪ INTRO] Before we get into it, let's go over what PFAS even is. PFAS stands for per- and polyfluoroalkyl substances. That's a bit of a mouthful, but it essentially covers molecules that are made of chains of carbon atoms with a bunch of fluorine atoms stuck to them. The bonds between those carbon and fluorine atoms are some of the strongest bonds of their kind, so they don't break down easily. Even when we want them to. Because PFAS are so sturdy, they're ending up in places we don't want them to be, like in our soil and drinking water.

We have a few ways to remove them already. We can use filters, activated carbon, or special resins to pull them out of water and soil. But just removing them doesn't get rid of them entirely. We still have to put them somewhere. An even better solution would be to completely destroy PFAS. Which is tricky because of those super-strong bonds… but scientists are working on it. So first, a few options for getting PFAS out of water. One thing you could try is killing them with bubbles using a technique called ultrasonication. Ultrasonication involves passing high-frequency sound waves through a solution containing PFAS.

These "ultrasound" waves are at a higher frequency than humans can hear, but they're a lower frequency than the ones used in medical imaging, like during pregnancy. When sound waves travel through the air, they act as pressure waves, stretching and compressing the air to move forward. They do the same thing when they pass through water. In the tiny fractions of a second when the solution expands, it pulls the water molecules apart enough to form tiny bubbles. Then, when the solution compresses, the bubbles implode. When that happens, they create really high temperatures and pressures in the areas they occupied.

Like, nearly 5,000 degrees Celsius and the pressure of about a thousand atmospheres. Those conditions are extreme enough to break down PFAS, leaving carbon dioxide, carbon monoxide, and fluoride minerals behind. And just in case that wasn't enough, the bubble collapse also blasts water molecules apart. In doing so, it forms highly reactive molecules called radicals. Atoms and molecules tend to have all their electrons neatly paired off. Most of the time, that's their most stable form. But sometimes, you can knock just one electron out, leaving one electron unpaired.

An atom or molecule with an unpaired electron is called a radical. Most radicals are unstable and extremely reactive. They'll do just about anything to get that lonely electron paired up again. When the bubble collapses, it forms hydrogen radicals and hydroxyl radicals. Those are so reactive that they can react with PFAS and break the carbon-fluorine bonds. Ultrasonication can break down more than 90% of PFAS that are common in drinking water, like perfluorooctanesulfonic acid or PFOA.

It actually works on soil too, as long as you mix the soil with water first. But there are thousands of PFAS chemicals out there. Depending on the particular ones in the water and the frequency of the sound waves, some might get broken down into shorter-chain PFAS and get stuck there. Still, it works pretty well for the ones we care about the most. So far, ultrasonication works well at breaking down PFAS in labs. But it's not quite ready to be deployed at large scale.

Scientists will need to find frequencies that can break down a bunch of different PFAS well at the same time. Ultrasonication is also kind of expensive, and it uses a lot of energy. So we'll want to work on that before sending it out into the world. Speaking of high pressures and temperatures, we don't necessarily need to rely on those tiny bubbles to do the work. We can destroy PFAS just as well if we heat and pressurize the entire solution. If you heat water to above 374 degrees Celsius and put it under more than 218 atmospheres worth of pressure, something really weird happens. Water goes into a supercritical state. It's neither a liquid nor a gas, but it has some properties of both.

More importantly, if there's any oxygen squeezed in there, supercritical water will make it react faster with a whole bunch of organic pollutants, including PFAS. Though we've known for a while that supercritical water speeds up these oxidation reactions, we've only started using them to treat PFAS in the last few years. And already the data is looking good. Supercritical water oxidation can destroy upwards of 95% of the PFAS in solution. In some cases, it can actually take out PFAS we don't even know are there.

See, we know to look for certain PFAS chemicals, like PFOA. But there are literally thousands of PFAS chemicals that we might not be explicitly checking for. They're still kicking around in the water, though, and supercritical water oxidation takes them out. The technique seems to work best with more concentrated streams of PFAS-contaminated water. If you need to concentrate the wastewater first, that could make it harder and more expensive to use at large scales. But there are commercially available systems that make use of this technology already. And in 2025, scientists showed that those systems worked on real-world

water samples contaminated with firefighting foam at a Space Force base. If neither of the previous techniques were weird enough for you, you could always turn to plasma. Shooting plasma at PFAS-contaminated water can break down those PFAS pretty darn quickly. Plasma is what you get when you rip a bunch of electrons off of the atoms in a gas. There are a lot of ways you can do that. But the upshot is that you end up with a bunch of free electrons, along with our old friends, radicals.

Scientists are still trying to figure out the exact pathway those plasma-based radicals go through to break down PFAS. And how well they do it depends on a lot of factors, including the PFAS themselves. We do know that long-chain PFAS tend to break down more easily than short-chain PFAS. So the shorter molecules need to get plasma-blasted for longer. Long-chain PFAS usually get broken down into carbon chemicals and fluoride ions. But like with all the other techniques we've covered, they can sometimes get stuck as short-chain PFAS that are harder to break apart,

so that limitation will need to be worked around. Plasma reactors are another technology that's currently available at scale. Commercial, mobile reactors can treat PFAS-contaminated water at a rate of several gallons per minute. Now, what if we want to get PFAS out of soil instead? One up-and-coming way to obliterate them is to smack them around a bunch with mining equipment. No, really! It's a process known as ball milling, and it's the same thing miners do to grind up ores.

First, you put PFAS-contaminated soil into a ball mill, which is a big rotating drum. Then you add in some steel or ceramic balls - hence, "ball milling." Usually, scientists add another chemical in with the PFAS to speed up the reaction. They might use something like potassium hydroxide, or a phosphate. Then you spin the drum and everything in it. When the balls tumble around in the drum, they pulverize pretty much everything in there. The tumbling action generates enough mechanical force to get those super-stable carbon-fluorine bonds to break down. When potassium hydroxide gets smacked around

in this mechanical ball pit, it forms hydroxyl radicals. Just like before, those hydroxyl radicals are so reactive that they can help kick the fluorine atoms off of PFAS. For certain PFAS, just banging the soil around can generate enough free electrons from whatever's in the dirt to destabilize the carbon-fluorine bond - no other chemicals needed. In some cases, ball milling can break down between 80 and 100 percent of PFAS in the soil in just a few hours. It can even break all the carbon-fluorine bonds. That leaves behind fluoride minerals and carbon compounds that break down normally.

Occasionally, though, it only partially breaks down larger PFAS, leaving smaller PFAS behind. So it's not always a perfect solution. Still, when it works, it really works. Most studies so far have focused on lab-scale setups called planetary ball mills. But some studies show that larger systems called horizontal ball mills can also work well. Horizontal ball mills are already used in mining. We already have the technology ready to go. One study successfully broke down PFAS in a 267-liter drum. So in theory it shouldn't be too hard to scale up.

If all else fails, we can remove PFAS from soil or water and then break them down by incinerating them. Like many other materials made of carbon, PFAS break down at high temperatures. For long-chain PFAS, that's typically a few hundred degrees Celsius. We already incinerate a lot of hazardous waste at those temperatures. Most commercial incinerators operate between 650 and 1,650 degrees Celsius. In theory, that should be enough to break down PFAS. And let's be real, whether we've planned for it or not, existing incinerators are almost certainly already sending some PFAS-laden materials up in smoke. It seems, then, like this should be an easy solution to our PFAS woes. But there's a catch.

We know that long-chain PFAS break down in incinerators. But we don't know what they break down into. If they don't end up breaking all the way down into carbon dioxide and fluoride, we could end up just releasing a bunch of different, shorter PFAS into the atmosphere. Right now, we don't have a way to check for all those thousands of different PFAS on their way out of the incinerator. So we don't know how much, if any, we're letting slip away. That means it's hard to know exactly how well this strategy works. So far, we don't have a perfect way to deal with PFAS. But we do have some pretty darn good leads. If we keep working to make them the best they can be,

there's hope we can turn PFAS from "forever chemicals" to something that's closer to "only-as-long-as-we-need-them" chemicals. [♪ OUTRO]