Breakthrough water filter removes 98% of toxic PFAS forever chemicals

Researchers at Flinders University have now developed a promising new approach that could help remove some of the hardest-to-capture forms of these long-lasting pollutants from water.

New Method Targets Hard-to-Remove PFAS

The team, led by Flinders ARC Research Fellow Dr. Witold Bloch, created specialized materials known as adsorbents that can effectively capture PFAS. Their method is particularly successful at trapping short-chain PFAS, which are notoriously difficult to remove with current water treatment technologies.

Their findings, published in the journal Angewandte Chemie International Edition, highlight the use of a nano-sized molecular cage designed to act as a highly selective 'PFAS trap'.

"While some long-chain PFAS can be partially removed using existing water treatment technologies, the capture of short-chain PFAS -- which are more mobile in water -- remains a major unresolved challenge," says project leader Dr. Witold Bloch, from Flinders University's College of Science and Engineering.

"We discovered that a nano-sized cage captures short-chain PFAS by forcing them to aggregate favourably inside its cavity. This unusually strong binding mechanism is different from that of traditional adsorbent materials."

How the Nano Cage Technology Works

To make the system effective, the researchers embedded these molecular cages into mesoporous silica, a material that typically does not bind PFAS on its own.

First author Caroline Andersson, a PhD candidate in chemistry at Flinders University, explains that adding the nanosized cage allows the material to remove a wide range of PFAS compounds from water, including those that are especially difficult to isolate.

"The most exciting aspect of this project was that we first conducted in-depth studies of how PFAS bind within the cage on the molecular level," she says. "That allowed us to understand the precise binding behaviour and then use that knowledge to design an effective adsorbent for PFAS removal."

High Efficiency and Reusability in Water Filtration

Laboratory tests showed that the new material can remove up to 98% of PFAS at environmentally relevant concentrations in model tap water.

"The adsorbent also demonstrated reusability, remaining highly effective after at least five cycles of reuse. These results highlight its potential for integration into water filtration systems for polishing drinking water at the final stage of treatment," adds Dr. Bloch.

"This research represents an important step toward the development of advanced materials capable of tackling one of the world's most persistent environmental contaminants," he concludes.

Growing Concern Over PFAS Pollution

PFAS chemicals are widely used in industrial manufacturing, aviation firefighting foam, and everyday consumer products. Over time, they can enter freshwater and marine environments, raising increasing concerns about potential health risks to humans, livestock, and wildlife.

Acknowledgements: The PFAS study was funded by Australian Research Council grants (FT240100330, DE240100664, DP230100587, CE230100021 and FT220100054), and Playford Trust PhD and ATSE Elevate PhD scholarships. The study used facilities including the MX1 and MX2 beamline at the ANSTO Australian Synchrotron, Australian Cancer Research Foundation detector, Flinders Analytical, Flinders Deepthought and the National Facility of the National Computational Infrastructure, and Microscopy Australia, enabled by NCRIS and the government of South Australia at Flinders Microscopy and Microanalysis.