Forever pollutants, or PFAS, are known for their remarkable stability: they resist degradation like few other substances. But a recent discovery could upend this reality.
Scientists have indeed demonstrated that exposure to very intense ultraviolet light is enough to trigger their destruction, without the need for chemical additives. This breakthrough offers a promising path to finally getting rid of these stubborn molecules.
Molecular representation of a perfluorooctanesulfonic acid, categorized as a PFAS.
Credit: University of Nebraska - Lincoln
These pollutants are found everywhere in the environment: drinking water, food packaging, even in human blood. Their nickname "forever pollutants" comes from their extremely stable chemical structure, which allows them to persist for decades. Current methods often merely filter them out without permanently eliminating them.
Researchers observed that under the effect of high-energy UV light, water breaks down into hydrogen radicals, which then attack PFAS molecules.
These hydrogen radicals are extremely reactive: they strip fluorine atoms from PFAS, gradually weakening the molecule. This process fragments it into smaller, less persistent compounds. The study shows that efficiency is highest for wavelengths below 300 nanometers.
The implications for pollution treatment are significant. As associate professor Zongsu Wei from Aarhus University, who led the research, explains, understanding this mechanism allows for designing technologies that truly destroy PFAS, rather than simply moving them. Current methods, like activated carbon filtration, only transfer the problem.
Despite this advance, researchers remain cautious. The degradation process is still slow and can generate intermediate compounds. This is not an immediate solution, but a fundamental step. By identifying a genuine chemical driver for PFAS destruction, science gains a clear direction to develop effective and sustainable methods.