Efficient removal of PFAS in groundwater and landfill leachate using iron-modified peat residues and electrochemical oxidation

Per- and polyfluoroalkyl substances (PFAS) are frequently found in soil, groundwater, and landfill leachate, in the vicinity where materials containing PFAS have been disposed of, or in areas where activities involving the use of aqueous film-forming foams (AFFF) have been executed. Removing PFAS via adsorption is a cost-effective and practical method to clean PFAS from contaminated waters. However, challenges arise with the inefficient adsorption of short-chain PFAS and the breakthrough of the contaminant, demanding further advancement. The current study investigates the removal of PFAS using a byproduct generated during the production of Float Adsorb (GP) in combination with electrochemical oxidation (EO). The byproduct was modified by incorporating iron oxyhydroxides. Batch experiments were conducted to assess PFAS adsorption onto the iron-modified material (Fe-P) and (GP), followed by column experiments simulating upscaled treatment. Electrochemical oxidation was then applied to degrade PFAS that broke through the adsorbent. Results showed that iron-coated adsorbent (Fe-P) had a higher capability to retain PFAS than uncoated material (GP). The removal of PFAS in groundwater on batch mode reached an average of 84.5 ± 1.1% using GP and 94.5 ± 0.3%∑11PFAS using Fe-P with an L/S ratio of 10. The EO following column treatment effectively degraded PFAS not adsorbed by the Fe-P adsorbent, showing promising potential for PFAS treatment in solutions. Up to 94% of ∑11 PFAS were removed in contaminated groundwater and 76% in leachate. Our study highlighted the potential of combined sorption and electrochemical oxidation methods to remediate PFAS in contaminated waters. • Fe-coated peat byproduct (Fe-P) retained PFAS in groundwater (GW) and leachate (LL) • Fe-P achieved 94.5% ∑11PFAS removal in batch (L/S 10) and 87% in column (L/S 2) • Electrochemical oxidation (EO) after sorption further reduced PFAS in solutions. • The Fe-P column and EO removed 94% and 76% ∑11PFAS in GW and LL respectively.