The degradation mechanisms of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) by different chemical methods: A critical review. (November 2021)

• Record Type: Journal Article
• Authors: Deng, Yun; Liang, Zhihong; Lu, Xingwen; Chen, Da; Li, Zhe; Wang, Fei
• Is Part Of: Chemosphere. Volume 283(2021)
• Publication Date: 2021-11
• Subjects: PFOS -- PFOA -- Photochemical -- Electrochemical -- Thermal treatment -- Degradation mechanisms; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.131168
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Per- and polyfluoroalkyl substances (PFASs) are a class of artificial compounds comprised of a perfluoroalkyl main chain and a terminal functional group. With them being applied in a wide range of applications, PFASs have drawn increasing regulatory attention and research interests on their reductions and treatments due to their harmful effects on environment and human beings. Among numerous studies, chemical treatments (e.g., photochemical, electrochemical, and thermal technologies) have been proved to be important methods to degradation PFASs. However, the pathways and mechanisms for the degradation of PFASs through these chemical methods still have not been well documented. This article therefore provides a comprehensive review on the degradation mechanisms of two important PFASs (perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS)) with photochemical, electrochemical and thermal methods. Different decomposition mechanisms of PFOA and PFOS are reviewed and discussed. Overall, the degradation pathways of PFASs are associated closely with their head groups and chain lengths, and H/F exchange and chain shortening were found to be predominant degradation mechanisms. The clear study on the degradation mechanisms of PFOA and PFOS should be very useful for the complete degradation or mineralization of PFASs in the future. Graphical abstract: Image 1 Highlights: H/F exchange and chain shortening were the predominant mechanism for PFOA and PFOS by three chemical methods. The sulfonate group in PFOS caused a desulfonation reaction during its degradation. Thermal treatment also behaves the decarbonization reaction for PFOA degradation.