Toxic forever chemicals can be removed from drinking water by a form of activated carbon commonly used to clean aquariums, a new study says.
Forever chemicals – per- and polyfluoroalkyl substances, or PFAS – are a class of industrial chemicals used for manufacturing numerous products such as non-stick cookware, cosmetics, stain-resistant fabrics, firefighting foams, food packaging, and waterproof clothing.
These substances, which persist in the environment for hundreds or even thousands of years, have been linked to decreased fertility in adults and developmental delays in children as well as to increased risk of some cancers.
Researchers have long been looking for ways to remove these chemicals from the environment or, at least, degrade them into harmless inorganic compounds.
Now, a new study published in the journal Environmental Science and Technology shows that heating PFAS with a common material called granular activated carbon, or GAC, can degrade these chemicals.
“You don’t need organic solvent or really high temperatures. Just heat the PFAS with granular activated carbon or GAC,” Feng Xiao, an author of the study from the University of Missouri in the US, says.
GAC, commonly used in air and water filters, contains granules of coal, wood or other carbon-rich materials that have been heated. It’s widely used to clean household aquariums and filter drinking water and can be easily purchased online.
The latest study shows that heating PFAS with GAC at about 300C leads to a 90 per cent mineralization of the PFAS, breaking the toxic substance down into harmless inorganic fluorine.
Such mineralisation of PFAS currently requires temperatures over 700C along with high pressure or solvents.
The new method is also more cost-effective and sustainable as GAC is inexpensive and can be reheated many times, Dr Xiao says. “Once GAC is involved, the thermal degradation of PFAS occurs much faster, and the mineralization is more intense,” he explains. “It’s not an expensive process compared to reverse osmosis and it can be done at a local scale with a regular furnace.”
The findings represent a breakthrough in managing PFAS.
“In the Midwest, we use a lot of herbicides and give animals a lot of pharmaceuticals. These substances can contain high amounts of PFAS,” Dr Xiao says. “Through this new removal method, we can drastically reduce the compounds’ presence in our lives.”
