Enhanced PFAS Degradation by Electro-Oxidation Using Granular Activated Carbon Anodes: Performance Improvement and Scale-Up Potential

Water contamination is a growing global concern, particularly due to the presence of per- and polyfluoroalkyl substances (PFAS) in drinking water, surface water, groundwater, wastewater, and sludge. These persistent pollutants pose significant health risks to humans and animals by accumulating in the body and affecting the immune system and liver. To address the emerging challenge of PFAS contamination, Granular Activated Carbon (GAC) is widely used as an adsorbent for PFAS removal in water and wastewater treatment plants. However, once saturated, it either requires additional GAC for continued use, or regeneration through processes such as chemical desorption that often produce highly concentrated secondary waste streams. To move beyond capture and address these limitations, advanced destructive treatment technologies are needed. A promising approach involves integrating GAC as a conductive material for use within electrochemical systems. This hybrid method not only retains GAC’s high adsorption capacity but also enables in situ degradation of PFAS. Despite its potential, the electrooxidation method for PFAS degradation and defluorination, particularly with GAC as an anode, remains underexplored.

 Initially, electro-oxidation using GAC alone showed limited effectiveness in the degradation and defluorination of various PFAS. In addition, PFAS adsorbed onto GAC were found to undergo minimal degradation when treated with chemical oxidants such as peroxydisulfate (PDS). However, experimental results demonstrate that incorporating PDS as a reactive oxidative species during electro-oxidation with a GAC anode enhances both the degradation and defluorination of a wide range of PFAS, including linear and branched, as well as saturated and unsaturated compounds, compared to systems operated without reactive oxidative species. These findings highlight the potential of GAC-based electrochemical oxidation as an innovative and effective approach for remediating diverse PFAS classes. This method reduces the need for frequent GAC replacement by enabling in situ degradation and defluorination of adsorbed PFAS, thereby enhancing both treatment efficiency and sustainability of water treatment systems. Furthermore, the widespread commercial use of GAC in existing water treatment infrastructure supports the potential for scaling up this remediation approach to real-world applications.