Field Demonstration of a Sonolysis Reactor for Treatment of PFAS-Contaminated Groundwater

Kinetics and Mechanism of Ultrasonic Defluorination of Fluorotelomer Sulfonates

“…This trend for polyfluoroalkyl FTSAs is opposite to what has been previously observed for perfluoroalkyl substances, where k US increased with increasing chain length. , For instance, at a similar frequency as our work, Campbell et al reported that C6 and C8 PFCAs and PFSAs degraded faster than C4 compounds and attributed the trend to adsorption behavior at the air–water interface of cavitation bubbles . Our observed trend does, however, agree with two studies that tested sonochemical degradation of PFAS mixtures which included multiple FTSAs. , Under select conditions ( f = 700 kHz) these studies observed that 4:2 FtS had a significantly faster first-order k US than 8:2 FtS in both PFAS-impacted groundwater and a synthetic mixture containing 24 PFAS compounds. Given the discrepancy in k US trends between FTSAs and perfluoroalkyl substances with respect to chain length, our results indicate that polyfluoroalkyl substances interact with cavitation bubbles differently than do perfluoroalkyl substances.…”

“…13 Our observed trend does, however, agree with two studies that tested sonochemical degradation of PFAS mixtures which included multiple FTSAs. 52,53 Under select conditions (f = 700 kHz) these studies observed that 4:2 FtS had a significantly faster first-order k US than 8:2 FtS in both PFASimpacted groundwater and a synthetic mixture containing 24 PFAS compounds. Given the discrepancy in k US trends between FTSAs and perfluoroalkyl substances with respect to chain length, our results indicate that polyfluoroalkyl substances interact with cavitation bubbles differently than do perfluoroalkyl substances.…”

“…Few studies have investigated ultrasonic degradation of polyfluoroalkyl substances. ,,, For instance, Kalra et al observed near-stoichiometric fluoride release of ultrasonic treatment of hexafluoropropylene oxide dimer acid, or Gen-X, and 6:2 fluorotelomer sulfonamidoalkyl betaine . However, more research is needed to continue to test the viability of ultrasound as a PFAS treatment technology.…”

Sonolysis and Super Critical Water Oxidation (SCWO): Development Maturity and Potential for Destroying PFAS

“…The rate‐limiting steps of acoustic destruction of PFAS are dependent on solution chemistry, such as ionic strength and surfactants affecting the surface tension of the solution and surface activity of PFAS, co‐contaminant molecules consuming acoustic energy, and dissolved gas affecting the temperature of cavitation. Furthermore, acoustic PFAS destruction rates are also affected by acoustic variables such as frequency of sound, power density and dissipation, wave interference, reactor pressure, and reactor geometry (Gole et al 2018; Cao et al 2020; Kalra et al 2021; Kulkarni et al 2022; Sidnell et al 2022).…”

Process to separate per‐ and polyfluoroalkyl substances from water using colloidal gas aphrons

“…The diverse range of PFAS chemistries, high stability of the C-F bond, and high water solubility make PFAS-impacted groundwater difficult to treat and render many of the conventional in situ and ex situ aqueous treatment technologies ineffective, including biodegradation, advanced oxidation processes, and thermal treatment (Crownover et al, 2019;Houtz & Sedlak, 2012;Javed, Lyu et al, 2020;Javed, Metz et al, 2020;McKenzie et al, 2015McKenzie et al, , 2016. While a few emerging destruction technologies such as sonochemical-and plasma-based treatment show promise (Kalra et al, 2021;Kulkarni et al, 2022;Nau-Hix et al, 2021;Ramos et al, 2022), adsorption on granularactivated carbon or ion exchange resins is the commercially preferred method to remove PFAS from water, especially in high flow scenarios such as drinking water treatment. However, adsorption methods are less effective in removing short-chain PFAS and results in residual waste of spent media (Gagliano et al, 2020).…”