Can perfluorooctanoic acid be effectively degraded using β-PbO2 reactive electrochemical membrane?

Abstract

Aqueous perfluorooctanoic acid (PFOA) elimination has raised significant concerns due to its persistence and bioaccumulation. Although β-PbO2 plate anodes have shown efficient mineralization of PFOA, it remains unclear whether PFOA can be effectively degraded using β-PbO2 reactive electrochemical membrane (REM). Herein, we assessed the performance of Ti/SnO2-Sb/La-PbO2 REM for PFOA removal and proposed a possible degradation mechanism. At a current density of 10 mA/cm2 and a membrane flux of 8500 (liters per square meter per hour, LMH), the degradation efficiency of 10 mg/L PFOA was merely 8.8%, whereas the degradation efficiency of 0.1 mg/L PFOA increased to 96.6%. Although the porous structure of the β-PbO2 REM provided numerous electroactive sites for PFOA, the generated oxygen bubbles in the pores could block the pore channels and adsorb PFOA molecules. These hindered the protonation process and significantly impeded the degradation of high-concentration PFOA. Quenching experiments indicated that •OH played dominant role in PFOA degradation. The electrical energy per order to remove 0.1 mg/L PFOA was merely 0.74 Wh/L, which was almost an order of magnitude lower than that of other anode materials. This study presents fresh opportunities for the electrochemical degradation of low-concentration PFOA using β-PbO2 REM.