Researchers funded by the U.S. National Science Foundation (NSF) and led by the University at Buffalo have created a filtration system that can effectively remove 80–90 percent of per- and polyfluoroalkyl substances (PFAS) from water.

Often called “forever chemicals” due to their inability to break down in the environment or human body, PFAS are often used for grease- and waterproof coatings for consumer goods like food packaging. Their presence in the environment is now ubiquitous, leading to human dietary exposure through drinking water and food sourced from plants and animals grown or raised in heavily polluted areas. PFAS exposure has been linked to negative health effects like an increased likelihood of some cancers. Some regulatory agencies have begun to take action against certain PFAS, such as the U.S. Environmental Protection Agency (EPA), which finalized legally enforceable limits for drinking water in April 2024, and the European Food Safety Authority (EFSA), which passed regulations to restrict PFAS in food packaging in January 2025.

The novel PFAS filtering technique is more effective than traditional, activated-carbon based methods, which, per a study published in American Chemical Society ES&T Engineering, is able to remove 80–90 percent of PFAS present in groundwater and sewage. The new technique involves the use of molecular nanocages, which are cage-like structures designed to capture, remove, and chemically deactivate hazardous substances from matrices. Previous studies have shown the efficacy of porphyrin nanocages in removing dyes, antibiotics, insecticides, and endocrine-disrupting chemicals from water.

Synthesized from a group of organic chemicals called porphyrins, the researchers’ nanocages were tested for their ability to absorb 38 types of PFAS. The nanocages removed 90 percent of PFAS from groundwater and 80 percent from unprocessed sewage. They also outperformed activated carbon in removing PFAS, especially from sewage. The researchers explained that carbon and other purification or filtration methods, such as ion exchange resins and reverse osmosis, tend to interact weakly with PFAS.

Additionally, nanocage filtration is less costly, energy-intensive, and high-maintenance than traditional techniques. The materials used to produce nanocages can be manufactured at scale, and the nanocages are modifiable to target only PFAS while not removing other water contents.

The first author on the study is Karla R. Sanchez-Lievanos, Ph.D.