Plasma water treatment for PFAS: Study of degradation of perfluorinated substances and their byproducts by using cold atmospheric pressure plasma jet

TL;DR

This study demonstrates that non-thermal plasma at atmospheric pressure can effectively degrade various PFAS compounds in water, revealing different mechanisms for different substances and highlighting potential for treating contaminated water.

Contribution

First to investigate plasma-based degradation mechanisms for ether-group PFAS like ADONA and GenX, providing insights into their breakdown pathways and potential for water treatment.

Findings

Successful laboratory removal of multiple PFAS compounds.

Distinct degradation mechanisms identified for different PFAS types.

Potential of plasma technology for treating newer PFAS substitutes.

Abstract

This study evaluates the effectiveness of non-thermal plasma at atmospheric pressure (NTP APPJ) for treating PFAS - contaminated water in different matrices. Successful removal of several perfluoroalkyl carboxylic acids (PFCAs) (C6 to C4), perfluroalkane sulfonic acids (PFSAs) (C8 to C4) and perfluropolyethers (PFPEs) (GenX and ADONA) PFAS compounds was achieved in laboratory scale experiments. Complex matrix effects influence degradation rates. Byproducts from the plasma treatment were investigated, revealing distinct degradation mechanisms for various PFAS compounds. For PFSAs and PFCAs, degradation involved electron transfer, bond breaking and subsequent reactions. Conversely, ADONA and GenX degradation initiated with ether-group cleavage, followed by additional transformation processes. Plasmabased technology shows potential for degradation of PFAS, especially for newer substitute compounds like ADONA and GenX. However, further research is needed to optimize plasma performance for complete mineralization of PFAS. This study also proposes a degradation mechanism for ADONA, marking a novel investigation into ether-group PFAS degradation with potential implications for further research and understanding toxicological implications.