The Achilles' Heel of Forever Chemicals — Scientists Find a Way to Break the Unbreakable

Aarhus University researchers have identified hydrogen radicals as the key mechanism that can destroy PFAS "forever chemicals" using only UV light and water — no added chemicals required. The discovery cracks open the carbon-fluorine bond that made these pollutants seemingly indestructible for decades.

PFAS — the "forever chemicals" lurking in water supplies, non-stick pans, and even human bloodstreams — have earned their nickname honestly. The carbon-fluorine bond at their core is the strongest in all of organic chemistry, making these compounds virtually indestructible in nature. They persist for decades. They accumulate. And until now, the best we could do was filter them out and move them somewhere else.

A team at Aarhus University in Denmark has just changed the equation.

Led by Associate Professor Zongsu Wei, the researchers discovered that hydrogen radicals — highly reactive particles generated when water is exposed to intense ultraviolet light — can systematically attack and dismantle PFAS molecules. No added chemicals. No exotic catalysts. Just light and water.

"We know that PFAS are extremely stable because of the strong carbon-fluorine bonds, and breaking those bonds is the main challenge," Wei said. "By identifying hydrogen radicals as a dominant driver, we now have a clearer direction for how to design more efficient and sustainable technologies to actually destroy these chemicals, rather than just removing them."

The mechanism works best under UV light at wavelengths below 300 nanometers. The hydrogen radicals strip fluorine atoms from the PFAS molecules one by one, gradually reducing them to smaller, less persistent compounds. It is not instant — the degradation is still relatively slow, and intermediate byproducts can form along the way — but it is the first time researchers have pinpointed exactly what drives the destruction process.

That clarity matters enormously. Most existing PFAS "solutions" — activated carbon filters, ion exchange resins, foam fractionation — merely relocate the problem. They pull PFAS out of water and concentrate it somewhere else, where it still needs to be dealt with. True destruction has been the holy grail, and this discovery provides the mechanistic roadmap to get there.

"Today, many technologies can filter PFAS out of water, but they do not eliminate them," Wei noted. "The real goal is degradation: to break the molecules down completely. Understanding the mechanism is essential if we want to achieve that in a green and scalable way."

The study, published in Environmental Science and Technology, challenges earlier assumptions about PFAS photolysis. Previous work had focused on other reactive species as the primary agents of breakdown. By demonstrating that hydrogen radicals are the dominant force, the Aarhus team has given future engineers a clear target to optimize for.

The timing could not be more pressing. PFAS contamination has been detected on every continent, including remote Arctic ice and deep ocean trenches. The CDC reports that PFAS are present in the blood of over 97% of Americans. Regulators worldwide — from the EPA to the EU — are tightening limits, but without true destruction technology, compliance becomes an endless game of chemical whack-a-mole.

The road from lab bench to water treatment plant is long, and Wei's team is careful not to overpromise. The photolysis process remains energy-intensive, and scaling it to municipal levels will require engineering breakthroughs of its own. But for the first time, the fundamental chemistry is no longer a mystery. We now know where forever chemicals are vulnerable — and that is where the fightback begins.

Sources: ScienceDaily, Innovation News Network, Aarhus University