CHAPTER 13: Mineralization of Next-generation Per- and Polyfluorinated Alkyl Substances by Use of Superheated Water

Per- and polyfluoroalkyl substances (PFASs) show unique characteristics such as high thermal and chemical stability, high surface activity, and no light-absorbing ability. As a result, they have been used in a wide variety of industrial and consumer applications. Although PFASs show many functionalities, they have environmentally negative features: high persistence in the environment and bioaccumulation [especially perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA)], and difficulties with waste treatment and recycling. In order to reduce the environmental impact of and to construct a recycling system for PFASs, it is necessary to convert their wastes to fluoride ions (i.e. mineralization). This chapter describes effective methodologies to mineralize next-generation PFASs (PFOS/PFOA alternative compounds and fluorinated ionic liquids) by use of superheated water combined with reductive or oxidative agents.