The Mineralization and Detoxification of PFOA Using a Sn/ZnO2@Ti4O7Anode

A Sn/ZnO 2 @Ti 4 O 7 anode was prepared using a combination of hydrothermal synthesis and discharge plasma sintering methods for the electrochemical degradation of perfluorooctanoic acid (PFOA). The introduction of Sn/ZnO 2 significantly increased the electrochemical active surface area (ECSA) and the oxygen evolution potential (OEP) of Ti 4 O 7 . A 97.6% degradation rate of PFOA can be achieved using a Sn/ZnO 2 @Ti 4 O 7 anode, at a current density of 40 mA/cm 2 , with the initial PFOA concentration of 10 mg/L, at a pH value of 5.69, and within 120 min. Radical quenching experiments indicated that direct oxidation was the main mechanism for PFOA degradation, contributing 82.5%. The degradation efficiencies of PFOA remained above 88% in Dongjiang and Zhujiang rivers (DJR and ZJR) matrixes, confirming the system’s resistance to complex matrix. The total organic carbon (TOC) removal ratio was 56.8%, and the defluorination ratio was 48% after electrolysis of 6 h. After 36 cycles of degradation, the degradation rate was 95.6%. The toxicity assessments indicated that the degradation intermediates were significantly less toxic than the parent PFOA. Graphical