Filtration material could absorb 'forever chemicals' at ultrafast rates

Researchers report a copper–aluminium layered double hydroxide (LDH) that can absorb long-chain PFAS up to about 100 times faster than current systems, and the captured PFAS were reported to be broken by heating the material to roughly 400–500°C.

New filtration material has been developed that researchers say soaks up long-chain PFAS at much faster rates than existing filters. The material is a layered double hydroxide (LDH) where some aluminium atoms are replaced by copper, which makes the surface positively charged and able to attract negatively charged PFAS. PFAS are a large group of persistent chemicals used since the 1950s that resist degradation and are linked to health issues. The research team reports benefits such as reuse potential and compatibility with existing infrastructure, while also noting there are challenges before wider deployment. Key findings: - The LDH material is reported to absorb long-chain PFAS at rates up to about 100 times faster than current filtration materials. - The LDH is made from copper and aluminium; the copper-substituted material is described as positively charged and broadly attractive to negatively charged PFAS. - PFAS are a family of roughly 15,000 chemicals that contain strong carbon–fluorine bonds, which make them persistent in the environment and the body, and many are associated with altered liver and thyroid function and some cancers. - Existing filtration methods such as granular activated carbon, reverse osmosis and ion exchange capture PFAS but leave contaminated media that require hazardous waste storage or high-temperature destruction that can produce toxic by-products or smaller PFAS. - The researchers report that heating the LDH with captured PFAS to about 400–500°C broke the PFAS bonds and left a disposable by-product, described in the paper as non-thermal compared with high-heat approaches. - The team reports the LDH can be used repeatedly and is compatible with existing infrastructure, which the researchers say could reduce some cost barriers, though deployment challenges remain. Summary: The researchers report the copper–aluminium LDH may offer a faster way to concentrate and then break long-chain PFAS bonds at relatively lower temperatures, which could affect approaches to pollution control. Undetermined at this time.