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Contamination from PFAS — the synthetic "forever chemicals" found in everything from nonstick cookware to firefighting foam — has spread into groundwater and drinking supplies affecting millions of people globally. Now researchers at Flinders University in Australia have developed a nano-sized molecular cage that can trap up to 98% of these persistent pollutants, including the short-chain varieties that existing water treatment methods struggle to capture.
The breakthrough, published in the journal Angewandte Chemie International Edition, centers on a specially designed molecular structure that acts as a highly selective PFAS trap. Unlike traditional materials, the cage forces short-chain PFAS molecules to cluster together inside its cavity, creating an unusually strong binding mechanism. "The capture of short-chain PFAS — which are more mobile in water — remains a major unresolved challenge," said project leader Dr. Witold Bloch, as reported by Science Daily.
To make the technology practical for water filtration, the team embedded the molecular cages into mesoporous silica, a porous material that on its own does not bind PFAS. The combination proved remarkably effective. Laboratory tests using model tap water at environmentally relevant concentrations showed removal rates of up to 98%. Crucially, the material also demonstrated reusability, maintaining high performance after multiple filtration cycles.
First author Caroline Andersson, a PhD candidate at Flinders, said the team's approach was grounded in understanding PFAS behavior at the molecular level before engineering the filter. "We first conducted in-depth studies of how PFAS bind within the cage on the molecular level," she said. "That allowed us to understand the precise binding behaviour and then use that knowledge to design an effective adsorbent."
The discovery could have significant implications for communities dealing with PFAS-contaminated water supplies. Current treatment technologies are often expensive and ineffective against the full range of PFAS compounds. A reusable, high-efficiency filter targeting both long-chain and short-chain variants would represent a major step forward in global water safety efforts.
