Perfluoroalkyl and polyfluoroalkyl substances (PFAS) have earned the nickname “forever chemicals” attributable to their extraordinary ability to persist within the environment long after they’re used.
Commonly utilized in consumer products and industrial applications attributable to their water- and grease-resistant properties, these synthetic compounds can now be found virtually in every single place within the environment.
While many chemicals decompose relatively quickly after disposal PFAS can stay for as much as 1,000 years. This durability makes it ideal to be used in firefighting foams, nonstick cookware, waterproof clothing, and even food packaging.
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However, due to their resilience, they persist in soil, water and even living organisms. They can accumulate over time and affect the health of ecosystems and other people.
Initial research has shown possible links between PFAS exposure and various health problems – including cancer, immune system suppression and hormonal imbalances. These concerns have led scientists to go looking for it effective ways to collapse these stubborn chemicals.
We are a team of researchers who’ve developed a chemical system that uses light to interrupt bonds between carbon and fluorine atoms. These strong chemical bonds help PFAS resist degradation. We published this work in Nature in November 2024, and we hope that this method may help combat the widespread contamination that these substances cause.
Why PFAS compounds are so difficult to interrupt down
PFAS compounds have carbon-fluorine bonds, one in every of the strongest in chemistry. These bonds make PFAS incredibly stable. They resist the degradation processes that normally break down industrial chemicals – including hydrolysis, oxidation and microbial degradation.
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Conventional water treatment methods can remove PFAS from waterbut these processes merely concentrate pollutants slightly than destroying them. The resulting PFAS-laden materials are typically sent to landfills. Even after disposal, they’ll find yourself back within the environment.
The current methods Breaking carbon-fluorine bonds is determined by using metals and really high temperatures. For example, Platinum metal will be used for this. This dependency makes these methods expensive, energy intensive, and difficult to use on a big scale.
How our recent photocatalytic system works
The recent method our team developed uses a purely organic photocatalyst. A photocatalyst is a substance that uses light to speed up a chemical response without being consumed. Our system uses the energy of low-cost blue LEDs to power a series of chemical reactions.
After the absorption of sunshine, the photocatalyst is created transfers electrons to the fluorine-containing molecules, breaking the stable carbon-fluorine bonds.
By directly attacking and degrading the molecular structure of PFAS, photocatalytic systems like ours hold the potential for complete mineralization. Complete mineralization is a process that converts these harmful chemicals into harmless end products equivalent to hydrocarbons and fluoride ions that readily break down within the environment. The broken down products can then be safely reabsorbed by plants.
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Possible uses and advantages
One of essentially the most promising features of this recent photocatalytic system is its simplicity. The setup essentially consists of a small vial that’s lit by two LEDs and has two small fans to maintain it cool in the course of the process. It works under mild conditions and doesn’t use metals often dangerous difficult to handle and might sometimes be explosive.
The system's reliance on light – a available and renewable energy source – could make it economically viable and sustainable. As we refine it, we hope that at some point it will probably run with minimal energy input, aside from the energy that powers the sunshine.
This platform may also convert other organic molecules containing carbon-fluorine bonds into beneficial chemicals. For example, 1000’s of Fluoroarenes are commonly available as industrial chemicals and laboratory reagents. These will be converted into constructing blocks for making a wide range of other materials, including medicines and on a regular basis products.
Challenges and future directions
Although this recent system shows potential, challenges remain. We are currently only capable of break down PFAS to a limited extent. Although our experimental setup is effective, significant scale-up is required to deal with the PFAS problem on a bigger scale. Additionally, large molecules with a whole bunch of carbon-fluorine bonds, like Teflon, don’t dissolve within the solvent we use for these reactions, even at high temperatures.
Therefore, the system cannot currently mine these materials and we’d like to do more research.
We also wish to improve the long-term stability of those catalysts. Currently, these organic photocatalysts degrade over time, especially when exposed to constant LED lighting. Therefore, developing catalysts that maintain their efficiency over the long run can be crucial for practical large-scale use. Developing methods to regenerate or recycle these catalysts without sacrificing performance may also be critical to scaling this technology.
With our colleagues on Center for Sustainable Photoredox CatalysisWe plan to proceed working on light-driven catalysis with the goal of discovering additional light-driven reactions solve practical problems. SuPRCat is a National Science Foundation-funded nonprofit Center for Chemical Innovation. The teams there are working to develop reactions for more sustainable chemical manufacturing.
The end goal is to create a system that may remove PFAS contaminants from drinking water at wastewater treatment plants, but that's still a great distance off. We would also wish to at some point use this technology to scrub soil contaminated with PFAS, making it secure for agriculture and restoring its role within the environment.
image credit : theconversation.com