Treatment Technologies for PFAS in Industrial Water
Perfluoalkyl chemicals are organic chemicals whose hydrogen atoms have been replaced by fluorine. Polyfluoroalkyls have had many of the hydrogens replaced by fluorine. More than 4,000 perfluorinated and polyfluorinated substances (PFAS) have been produced since they were developed in the 1940s. More than 1,000 are listed in the U.S. Environmental Protection Agency’s (EPA) Toxic Substances Inventory of commercial chemicals.
Fluorination introduces many unusual and useful properties. The chemical, or at least part of it, becomes hydrophobic (repelled by water), whereas other parts, such as a carboxylic acid unit, become more ionic and water soluble. The carbon-fluorine bond is resistant to hydrolysis and other chemical processes and biological degradation, so those chemicals are not readily metabolized after ingestion and are stable in the environment and not removed by standard decomposition mechanisms. Thus, they can be detected in water and soils for many years after they have been introduced. They may also have unusual toxicological properties, partly because they will not be metabolized or eliminated rapidly and will accumulate in the person or animal that has ingested or inhaled them. For these reasons, fluorinated chemicals have become objects of major international regulatory interest aimed at preventing their introduction into the environment and their removal when they are detected in media like food or water.