UV-made hydrogen radicals shown to break down PFAS
Aarhus University researchers say intense UV light can generate reactive particles from water that attack PFAS without added chemicals.
By Priya Raghavan · Science Reporter
3 min read
Researchers at Aarhus University say they have identified a chemical process that can break down PFAS, a group of pollutants known for resisting degradation in water, ecosystems and the human body. The finding matters because many current treatment methods can capture PFAS but do not destroy the compounds, according to the university.
The study, published in Environmental Science, found that intense ultraviolet light can produce hydrogen radicals from water and that those reactive particles play a central role in degrading PFAS. Aarhus University said the process does not require added chemicals.
PFAS, short for per- and polyfluoroalkyl substances, are synthetic chemicals used since the 1940s, according to Aarhus University. The university said they have been found in products including waterproof clothing, food packaging, firefighting foam and non-stick cookware.
Light-driven chemistry targets strong bonds
The challenge in destroying PFAS comes from their stability, which is tied to strong carbon-fluorine bonds, according to Associate Professor Zongsu Wei, who led the study. Aarhus University said the research points to hydrogen radicals as a dominant driver of the breakdown reaction, rather than other reactive species emphasized in earlier work.
In the process described by the researchers, hydrogen radicals attack PFAS molecules and remove fluorine atoms over time. Aarhus University said that reaction breaks the compounds into smaller substances that persist less in the environment.
The team reported that the degradation worked best under high-energy ultraviolet light, especially at wavelengths below 300 nanometers. The study used intensified simulated solar light, according to the journal reference listed by Aarhus University.
Wei said identifying the main reactive particle gives researchers a clearer basis for designing systems meant to destroy PFAS rather than shift them from one place to another. He said understanding the mechanism is needed to pursue greener and more scalable degradation methods.
No immediate cleanup fix
Aarhus University cautioned that the research does not amount to a ready-made treatment system. The university said the reaction remains relatively slow, and intermediate compounds can appear as PFAS molecules break down.
The finding still provides a target for future work on water treatment, according to the researchers. By showing which chemical species drives the reaction, the study could help guide designs for more effective PFAS destruction technologies.
PFAS contamination has drawn environmental and public health concern because the compounds break down slowly and can accumulate in water, soil, wildlife and people, according to Aarhus University. The university said exposure has been linked to health concerns including cancer, liver damage and hormone disruption.
The study was authored by Lu Bai, Shuang Luo, Jan Thøgersen, Xingaoyuan Xiong, Zheng Guo and Zongsu Wei. Aarhus University listed the paper as “Mechanistic Insights into Per- and Polyfluoroalkyl Substance (PFAS) Photolysis under Intensified Simulated Solar Light,” published in Environmental Science in 2026 with DOI 10.1021/acs.est.5c16178.
This story draws on original reporting from ScienceDaily.