Researchers have developed a way to break down long-lasting PFAS compounds using light

PFAS resilience means that they persist in soil, water and even living organisms. They can accumulate over time and affect the health of both ecosystems and humans.

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Some initial research has shown potential links between PFAS exposure and various health issues — including cancers, immune system suppression and hormone disruption. These concerns have led scientists to search for effective ways to break down these stubborn chemicals.

A team of researchers who developed a chemical system that uses light to break down bonds between carbon and fluorine atoms. These strong chemical bonds help PFAS resist degradation. They published this work in Nature in November 2024, and we hope this technique could help address the widespread contamination these substances cause.

Why PFAS compounds are so hard to break down

PFAS compounds have carbon-fluorine bonds, one of the strongest in chemistry. These bonds make PFAS incredibly stable. They resist the degradation processes that usually break down industrial chemicals – including hydrolysis, oxidation and microbial breakdown.

The carbon-fluorine bonds in PFAS, like this one, perfluoroundecanoic acid, make the molecules very stable. Graphic by Bert.Kilanowski/Wikimedia Commons

Conventional water treatment methods can remove PFAS from water, but these processes merely concentrate the contaminants instead of destroying them. The resulting PFAS-laden materials are typically sent to landfills. Once disposed of, they can still leach back into the environment.

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The current methods for breaking carbon-fluorine bonds depend on use of metals and very high temperatures. For example, platinum metal can be used for this purpose. This dependence makes these methods expensive, energy-intensive and challenging to use on a large scale.

How this new photocatalytic system works

The new method our team has developed uses a purely organic photocatalyst. A photocatalyst is a substance that speeds up a chemical reaction using light, without being consumed in the process. Our system harnesses energy from cheap blue LEDs to drive a set of chemical reactions.

After absorbing light, the photocatalyst transfers electrons to the molecules containing fluorine, which breaks down the sturdy carbon-fluorine bonds.

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By directly targeting and dismantling the molecular structure of PFAS, photocatalytic systems like ours hold the potential for complete mineralization. Complete mineralization is a process that transforms these harmful chemicals into harmless end products, like hydrocarbons and fluoride ions, which degrade easily in the environment. The degraded products can then be safely reabsorbed by plants.

Photocatalysis refers to accelerating a reaction by using light particles, called photons. Photo provided by Miyake Group

Potential applications and benefits

One of the most promising aspects of this new photocatalytic system is its simplicity. The setup is essentially a small vial illuminated by two LEDs, with two small fans added to keep it cool during the process. It operates under mild conditions and does not use any metals, which are often hazardous to handle and can sometimes be explosive.

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The system’s reliance on light – a readily available and renewable energy source – could make it economically viable and sustainable. As we refine it, we hope that it could one day operate with minimal energy input, outside of the energy powering the light.

This platform can also transform other organic molecules that contain carbon-fluorine bonds into valuable chemicals. For instance, thousands of fluoroarenes are commonly available as industrial chemicals and laboratory reagents. These can be transformed into building blocks for making a variety of other materials, including medicines and everyday products.

Challenges and future directions

While this new system shows potential, challenges remain. Currently, we can degrade PFAS only on a small scale. While our experimental setup is effective, it will require substantial scaling up to tackle the PFAS problem on a larger level. Additionally, large molecules with hundreds of carbon-fluorine bonds, like Teflon, do not dissolve into the solvent we use for these reactions, even at high temperatures.

As a result, the system currently can’t break down these materials, and we need to conduct more research.

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Taxonomy

• PFAS