Comparative evaluation of quantifiable PFAS generated as byproducts from polytetrafluoroethylene (PTFE) incineration

• We quantified PFAS byproducts generated from PTFE incineration. • The temperature-dependent behavior of PFAS was evaluated. • Total PFAS levels were suppressed at temperatures above 850 °C. • The behavior of 13 PFCAs and 4 PFECAs was quantitatively characterized. • The distribution of individual PFAS across eight media was determined. There is a need for quantitative data on generation of per- and polyfluoroalkyl substances (PFAS) during incineration of polytetrafluoroethylene (PTFE) at the end of the lifecycle of PTFE products. This study quantified the temperature-dependent generation of PFAS byproducts that were formed during the thermal decomposition of PTFE in an oxidizing atmosphere. The PFAS analyzed were C 4 to C 18 perfluoroalkyl carboxylic acids (PFCAs) and four compounds of perfluoroalkyl ether carboxylic acids (PFECAs). As a result of the blank tests, trace amounts of PFAS were detected. Therefore, the results for byproduct PFAS were discussed after subtracting the blank values. After incineration, total PFAS byproducts formed at a maximum of 0.028 % (700 °C) and a minimum of 6.9 × 10⁻⁶ % (950 °C) relative to the PTFE input. Comparative evaluation of total PFAS byproducts generated during PTFE incineration showed that the changes observed were comparable to or were one order of magnitude lower than those observed for PFAS byproducts generated during the thermal decomposition of perfluorooctanoic acid (PFOA) and perfluorooctadecanoic acid (PFOcDA). Analysis of individual PFAS data revealed relatively high levels of short-chain PFCAs as byproducts, high-temperature suppression of long-chain PFCAs, characteristic generation patterns of PFECAs, and trace residues of PFOA at elevated temperatures. Based on the distribution behavior of individual PFAS by medium, we found that in addition to adsorption by resins, capture using solutions such as toluene or NaOH is necessary depending on the carbon number. This report demonstrated that decomposition of PTFE at temperatures above 850 °C can suppress the generation of PFAS byproducts to the levels equivalent to or lower than those produced during decomposition of regulated PFAS.