Removal of PFAS from aqueous solution using PbO2 from lead-acid battery

Whilst advanced electrochemical oxidation can break down per- and polyfluoroalkyl substances (PFAS), the requirement for expensive electrode materials usually prevents its widespread application. Here we use an industrial material of lead peroxide (PbO2) from a lead-acid battery to break down PFAS including perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and 1H,1H,2H,2H-perfluorooctanesulfonic acid (6:2 FTS). By optimising the PbO2 panel (activating and doping) and working conditions including supporting electrolyte (1 L 10 mM Na2SO4), initial concentration (10 mu M), temperature (room temperature), current density (5 A for a 10 cm x 10 cm PbO2 panel) etc., we successfully remove > 99% PFAS (individual PFAS monitored via HPLC-MS) whilst mineralising similar to 59% PFOA (defluorination, F- released and monitored via F-ISE, fluoride-ion selective electrode). By studying the pseudo-first-order kinetics of the PFAS breakdown (0.0028-0.007 min(-1)) and defluorination (0.84-5.9 x 10(-8) min(-1)), we assign the difference to the adsorption of PFAS on the PbO2 panel and the appearance of intermediates before the full defluorination. The leaked HF gas (similar to 10(-5) M, collected using 0.25 L 0.1 M NaOH) and Pb2+ (similar to 12 mu M, or similar to 2.5 ppm) are also confirmed. This study employs an economic industrial material, highlights the contribution of adsorption towards the PFAS removal and breakdown, and identifies the possible leakage of secondary contaminants. (C) 2018 Elsevier Ltd. All rights reserved.