Contamination with per- and polyfluoroalkyl substances (PFAS) is widespread in groundwater, surface water, and even drinking water, impacting millions of people around the world.
Flinders University researchers have developed a promising new approach that could help remove some of the most elusive forms of these long-lasting pollutants from water.
New method targets hard-to-remove PFAS
A team led by Flinders ARC researcher Dr Witold Block has created a special material known as a sorbent that can effectively capture PFAS. Their method is particularly successful in capturing short-chain PFAS, which are notoriously difficult to remove with current water treatment technologies.
Their findings were published in the journal Applied Chemistry International Editionhighlighting the use of nanosized molecular cages designed to act as highly selective “PFAS traps.”
“While some long-chain PFAS can be partially removed using existing water treatment technologies, capturing the more mobile short-chain PFAS in water remains a major open challenge,” said project leader Dr Witold Block from Flinders University’s School of Science and Engineering.
“We found that the nanosized cages trap short-chain PFAS by favorably aggregating them within their cavities. This unusually strong binding mechanism is different from that of traditional adsorbent materials.”
How nanocage technology works
To make this system effective, the researchers embedded these molecular cages in mesoporous silica, a material that does not normally bind PFAS on its own.
Lead author Caroline Anderson, a PhD candidate in chemistry at Flinders University, explains that by adding nano-sized cages, the material can remove a wide range of PFAS compounds from water, including particularly difficult-to-separate compounds.
“The most exciting part of this project is that we performed the first detailed study of how PFAS binds within the cage at a molecular level,” she says. “This allowed us to understand the exact binding behavior and use that knowledge to design effective sorbents for PFAS removal.”
High efficiency and reusability of 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 sorbent also demonstrated reusability and remained highly effective after at least five reuses. These results highlight the potential for the sorbent to be integrated into water filtration systems for purifying drinking water at the final stage of treatment,” Dr. Block added.
“This research represents an important step towards developing advanced materials that can address one of the world’s most stubborn environmental pollutants,” he concluded.
Growing concerns about PFAS contamination
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 concerns about potential health risks to humans, livestock, and wildlife.
Acknowledgments: The PFAS research 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 ANSTO Australian Synchrotron’s MX1 and MX2 beamlines, the Australian Cancer Research Foundation Detector, Flinders Analytical, Flinders DeepThought and the National Computing Infrastructure National Facility, and Microscopy Australia, a collaboration between NCRIS and Flinders Microscopy and Microanalysis Ltd. of South Australia.
