Destruction of perfluorooctanesulfonate (PFOS) in a batch supercritical water oxidation reactor

Brian R Pinkard; Shreyas Shetty; Derek Stritzinger; Christopher Bellona; Igor V Novosselov

doi:10.1016/j.chemosphere.2021.130834

Destruction of perfluorooctanesulfonate (PFOS) in a batch supercritical water oxidation reactor

Chemosphere. 2021 Sep:279:130834. doi: 10.1016/j.chemosphere.2021.130834. Epub 2021 May 18.

Authors

Brian R Pinkard¹, Shreyas Shetty², Derek Stritzinger², Christopher Bellona³, Igor V Novosselov⁴

Affiliations

¹ University of Washington, Mechanical Engineering Department, Seattle, WA, 98195, USA; Aquagga, Inc., Tacoma, WA, 98421, USA. Electronic address: pinkardb@uw.edu.
² University of Washington, Mechanical Engineering Department, Seattle, WA, 98195, USA.
³ Colorado School of Mines, Civil and Environmental Engineering Department, Golden, CO, 80401, USA.
⁴ University of Washington, Mechanical Engineering Department, Seattle, WA, 98195, USA; University of Washington, Institute for Nanoengineered Systems, Seattle, WA, 98195, USA.

PMID: 34134433
DOI: 10.1016/j.chemosphere.2021.130834

Abstract

Effective technologies are needed for the destruction of per- and polyfluoroalkyl substances (PFAS). One promising technology is supercritical water oxidation (SCWO), which can be accommodated in batch or continuous reactors. Many PFAS-laden wastes consist primarily of solid particles, and batch SCWO processing may offer safe end-of-life PFAS destruction for these feedstocks. In this study, perfluorooctanesulfonate (PFOS) is reacted via supercritical water oxidation in a batch reactor at temperatures between 425 and 500 °C and residence times from 0 to 60 min, to determine the effect of both parameters on the extent of destruction and defluorination. Analysis of liquid products via targeted LC-QToF-MS does not indicate production of intermediate fluorocarbons. However, a low fluorine mass balance at temperatures of 425 and 450 °C may indicate the existence of fluorinated species in the gaseous and/or liquid product which are not detected by targeted analysis. Destruction and defluorination efficiencies are determined for each tested condition, with a maximum 70.0% PFOS destruction and 78.2% defluorination achieved after 60 min of reaction at 500 °C.

Keywords: Defluorination; Oxidation; PFAS; PFOS; Reaction mechanisms; Supercritical water.

MeSH terms

Alkanesulfonic Acids*
Fluorocarbons*
Oxidation-Reduction
Water
Water Pollutants, Chemical*

Substances

Alkanesulfonic Acids
Fluorocarbons
Water Pollutants, Chemical
Water
perfluorooctane sulfonic acid