BY MARIA BURKE
Researchers at the University of Adelaide, Australia, have developed a sunlight-activated material that can degrade per- and polyfluoroalkyl substances (PFAS) in water, breaking down the pollutant into harmless components, including fluoride. Their discovery is a promising low-energy solution for PFAS remediation, with potential applications in water treatment and environmental cleanup.
PFAS are used in a range of goods such as cookware, firefighting foams and water-repellent fabrics. Their strong carbon-fluorine bonds mean they are hard to break down. As they are resistant to degradation by traditional water treatment methods, they accumulate in the environment and human bodies.
‘Many water contaminants are degraded by adding a reactive chemical that binds to the carbon,’ lead researcher Cameron Shearer at the University of Adelaide explains. ‘However, in PFAS molecules, the carbon atoms are protected in such a way that makes this process nearly impossible.’
One treatment method under investigation is semiconductor-assisted photocatalysis. Shearer’s team chose cadmium indium sulfide (CdIn2S4) as the photocatalyst because of its high visible light-harvesting capacity and high reduction potential. They also noted that it had not been investigated for PFAS degradation before.
The team fabricated CdIn2S4 micro-pyramids and tested them on both simulated lab samples and samples from a contaminated facility in South Australia, experimenting with the best reaction conditions, such as the light source and the light power. Under optimal conditions over 24 hours, they found that the catalyst achieved almost complete degradation and defluorination of PFAS as a result of photoelectron reduction (Small, 2025, DOI: 10.1002/smll.202504601).
‘The materials we have developed could be used as part of PFAS-treatment chains that first capture and concentrate PFAS in water, which can then be degraded through exposure to our light-activated materials,’ Shearer says. ‘The resultant fluoride can be isolated and used in healthcare products such as toothpaste or as additives to fertilisers. The team plans to improve the stability of the materials so they can be applied to large-scale systems.
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