Researchers have developed new filtration technologies capable of absorbing 'forever chemicals' at an 'ultrafast' rate, potentially revolutionising pollution control. The breakthrough, reported in a recent paper, uses a layered double hydroxide (LDH) material made from copper and aluminium to capture long-chain PFAS up to 100 times faster than current systems.
PFAS, or per- and polyfluoroalkyl substances, are known as 'forever chemicals' because their extremely strong carbon-fluorine bonds prevent them from degrading. Used since the 1950s in consumer and commercial products for their water and oil repellence and heat resistance, there are around 15,000 different PFAS chemicals. Many are toxic, linked to liver and thyroid issues and various cancers, and they persist in the environment and human bodies for decades.
Current filtration methods, such as granular activated carbon, reverse osmosis and ion exchange, absorb PFAS but require storage in hazardous waste facilities or high-temperature thermal destruction, which produces toxic byproducts or breaks PFAS into smaller, still harmful molecules. The new LDH material, developed at Rice University's Water Institute, works by soaking up and concentrating PFAS at high levels without extreme heat.
According to Michael Wong, director of the institute, the LDH material differs from previous versions by replacing some aluminium atoms with copper. This gives the material a positive charge that attracts and absorbs a broad array of negatively charged PFAS. 'It just soaks it in to the order of 100 times faster than other materials that are out there,' he said. Heating the loaded material to 400–500°C – a relatively low temperature – breaks the carbon-fluorine bonds, leaving a safe, disposable byproduct.
While many new PFAS elimination systems fail at scale, the researchers claim the LDH material has a strong absorption rate and can be reused repeatedly with existing infrastructure, reducing cost barriers. 'This material is going to be important for the direction of research on PFAS destruction in general,' Wong added.
