Thermal- and photo-induced degradation of perfluorinated carboxylic acids: Kinetics and mechanism

Electrochemical degradation of per- and polyfluoroalkyl substances (PFAS) using low-cost graphene sponge electrodes

“…The general trend was that higher recoveries in the AOF analysis S17 were observed for PFCAs compared with PFSAs, and that higher recoveries are observed with the shortening of the fluorinated chain length, i.e., the recoveries were increasing in the order PFOS<PFHxS<PFBS, and PFOA<PFHxA<PFBA (Table S2). Cleavage of the C7-C8 bond in PFOA was found to be thermodynamically more favorable than defluorination at temperatures below 1000 °C 13,14 . Although the combustion in the AOF analysis was conducted at 1,100 C (Text S4), it may not be complete and the formation of shorter chain fluorinated byproducts cannot be excluded, thus leading to lower AOF recoveries for longer chain PFOA and PFOS.…”

Photo-chemical/catalytic oxidative/reductive decomposition of per- and poly-fluoroalkyl substances (PFAS), decomposition mechanisms and effects of key factors: a review

“…197 Besides sonication, a comprehensive study of PFCAs ( n = 1–9) reported that thermal-assisted photolysis of PFCAs shorten the removal time, as 40% and 70% of PFOA was degraded after 12 h in 25 °C and 60 °C, respectively. 198 Also, the combination of Fe 0 /granular activated carbon (GAC) micro-electrolysis with photochemical processes increased PFAS decomposition efficiency. 199 Introduction of Fe 0 /GAC micro-electrolysis in VUV system enhanced utilization of photon intensity and increased (∼8%) PFOA defluorination efficiency.…”

Quantification of per‐ and polyfluoroalkyl substances with a modified total organic carbon analyzer and ion chromatography

“…Fluorine recovery was similar for all PFCAs, except for PFPrA with 36% of fluorine recovered. Decomposition of PFCAs is thought to proceed first through homolysis of the C-C bond between the carboxylic acid and perfluoroalkyl chain, followed rapidly or simultaneously by loss of fluorine from the first alkyl carbon (Liu et al, 2017;Xiao et al, 2020). The pathway is thought to be significantly different for PFPrA due to the limited number of fluoroalkyl carbon atoms (=2).…”