PFAS–Container Interaction: A Case Study of PFOS Defluorination with Acoustic Cavitation

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a large class of ubiquitous and persistent environmental contaminants. Due to the extremely stable carbon-fluorine bonds, PFAS are difficult to destruct. Increasing research efforts are focusing on PFAS defluorination, and one of the key challenges is tracking down the breakdown products and achieving a reasonable mass balance. In this study, we demonstrate one vital but often overlooked aspect of PFAS destruction studies, using perfluorooctanesulfonic acid (PFOS) destruction with acoustic cavitation as a case. This study showed that PFOS–container interactions can significantly impact the destruction efficiency and provided an example whereby these interactions may be prevented using surface coating. A showcase of mass balance for PFAS defluorination using acoustic cavitation was also investigated by employing targeted analysis [liquid chromatography-mass spectrometry (LC-MS)] and complementary untargeted analysis (total organofluorine measurement). This study demonstrated the necessity for a thorough consideration of all aspects in PFAS destruction experiments and the necessity of early adoption of total organofluorine measurements.