Made from an organic nanoporous material engineered specifically to target PFAS, the nanocage system removed 80 % of PFAS from sewage and 90 % from groundwater in study tests, all while showing minimal environmental side effects.
PFAS, often referred to as “forever chemicals,” are widely used in products like food packaging, nonstick cookware, and waterproof fabrics. They’re known for their persistence in the environment and resistance to degradation, making them notoriously hard to remove from water.
Long-term exposure to PFAS has been linked to serious health risks, including decreased fertility, developmental issues in children, and an increased risk of certain cancers. Finding safe and effective ways to eliminate PFAS from groundwater and wastewater remains a pressing national concern.
While molecular nanocages have been proposed before as potential tools for pollutant removal, this study highlights their real-world performance in filtering out PFAS. Thanks to their stable structure and chemical design, these nanocages not only capture and remove harmful substances but may also help break them down. The researchers also noted potential applications in air filtration - for example, removing harmful gases.
The team designed porphyrin-based nanocages with high selectivity, stability in water, and rapid sorption capabilities. In tests, the material consistently removed around 90 % of 38 different PFAS compounds from mixed water samples.
The nanocages were synthesized from porphyrins, a class of organic molecules already known for removing other pollutants like dyes, antibiotics, and hormone-disrupting chemicals from water. In this study, the researchers assessed their effectiveness against a broad range of PFAS, including GenX - a chemical commonly found in nonstick and industrial products.
Compared to activated carbon, a widely used but often limited PFAS removal method, the nanocages showed superior performance, especially in raw sewage. The study also highlighted key advantages of nanocages over other purification methods like ion exchange resins and reverse osmosis, which often require high energy input and come with higher maintenance costs.
Porphyrin-based nanocages offer a potentially practical solution to the challenges of PFAS removal. The material can also be mass-produced at scale, and the cages are modifiable to remove PFAS only while leaving other water contents alone.
Samy El-Shall, Program Director, Division of Chemistry, US National Science Foundation
Journal Reference:
Sanchez-Lievanos, R.K, et al. (2024) Synthesis and Evaluation of Cationic Porphyrin-Based Organic Nanocages for the Removal of 38 PFAS from Water: Experimental, Theoretical, and Eco-toxicological Insights. American Chemical Society. doi.org/10.1021/acsestengg.4c00639.