Scientists Built a Membrane That Breaks Down ‘Forever Chemicals’ Instead of Just Trapping Them | Mihai Andrei, ZME Science
Removing forever chemicals from water is one thing. But actually destroying them is another.
Now, scientists have developed a membrane that appears capable of doing both. In a 58-day laboratory experiment, the device removed more than 90% of each of six notorious PFAS chemicals from contaminated water. It also stripped away 83% of the fluorine targeted by the treatment.
Forever troubles
PFAS (short for per- and polyfluoroalkyl substances) have earned their nickname for good reason. They’re a group of thousands of synthetic chemicals that can persist in the environment for decades because they resist breaking down.
Manufacturers have used them for decades in everything from nonstick cookware and waterproof fabrics to food packaging and firefighting foams. They’re useful commercially because they’re so durable. Unfortunately, that’s also why they’re so problematic. They persist as pollutants in rivers, groundwater, soil, and living organisms. Yes, that includes the human body.
“PFAS contain an exceptionally strong carbon-fluorine bond, which makes them highly resistant to breakdown,” explained Vasilis Vasiliou at the Yale School of Public Health, in an unrelated 2025 interview.
“As a result, they persist in the environment for decades or longer — in water, soil, and even living organisms. Their environmental and biological persistence means they can accumulate over time, raising long-term concerns for ecosystems and public health.”
Exposure to certain PFAS has been associated with health problems, including immune-system disruption, elevated cholesterol, reproductive effects, and some cancers.
So, understandably, researchers are trying to find ways to get rid of them.
Removing vs destroying
Existing treatment technologies can remove PFAS from water pretty well. Activated carbon attracts and holds the molecules, while reverse osmosis pushes water through membranes that reject contaminants.
But neither process necessarily destroys the chemicals.
Instead, the PFAS accumulate in spent filters or concentrated waste streams that still require disposal or further treatment. Researchers led by Bruce Rittmann at Arizona State University, working with collaborators in the United States, China, and Singapore, determined that they could come up with a better approach: using reactive hydrogen to replace fluorine atoms in PFAS molecules.
Their new system relies on microscopic hollow fibers coated with nanoparticles of palladium, a precious metal commonly used as a catalyst.
Hydrogen gas flows through the inside of these fibers. As it reaches the palladium coating, the metal splits hydrogen molecules into highly reactive individual hydrogen atoms. Meanwhile, PFAS molecules dissolved in the surrounding water attach to the palladium surface.
“The palladium attracts the PFAS molecule, and the palladium attracts the hydrogen and puts them together,” Rittmann explained in an Arizona State University news release.
From there, hydrogen can replace fluorine atoms in the pollutants, gradually dismantling the chemical structures that make them so persistent. Scientists call this process hydrodefluorination.
A realistic test
There isn’t just one forever chemical. PFAS are a sprawling family of more than 10,000 compounds, and their different chemical structures can make some much harder to destroy than others.
To see how their membrane handled this diversity, the researchers first tested six PFAS which are among the most common ones. These include the notorious PFOA and PFOS, as well as PFNA, PFHxS, PFBS, and GenX.
In lab tests, this worked for longer-chain PFAS like PFNA better. Shorter-chained PFAS, especially GenX, proved more resilient. Even so, the researchers detected breakdown products from GenX as well.
Next came the more realistic test: treating a mixture of all six chemicals continuously.
For 58 days, the researchers passed contaminated water through the membrane reactor. Each PFAS entered at a concentration of 50 micrograms per liter. This is the concentration of a heavily polluted site.
The results were encouraging. The system removed between 93% and 99% of each chemical from the water. Much of that was destroyed. Across all six chemicals, the reactor achieved an overall defluorination efficiency of 83%.
Can we use it “in the wild”?
While the results are encouraging, the entire system processed only about four liters of water in total. The continuous experiment operated at just 0.05 milliliters per minute.
Much more work is needed to establish whether the technology can treat large volumes of real-world water efficiently. The experiments also used acidic conditions, at pH 4, and high concentrations. With lower concentrations, they might lose some of their efficiency.
Then, there’s the cost.
Palladium is expensive, and the researchers reported approximately 10% cumulative palladium loss from the membrane over the 58-day experiment. Future systems would need to reduce catalyst costs, improve durability, and evaluate potential metal release.
Still, the technology may not need to treat an entire municipal water supply to become useful.
One possibility is to pair it with conventional filters. Existing systems could first capture PFAS and concentrate them into a smaller volume of contaminated waste. The catalytic membrane could then treat that concentrated stream, destroying pollutants that would otherwise remain an expensive disposal problem.
That would represent an important change in how engineers approach PFAS contamination. For now, we need all the help we can get in our fight against PFAS.
Read more:
zmescience.com/science/news-…