Highly efficient and stable Zr-doped nanocrystalline PbO2 electrode for mineralization of perfluorooctanoic acid in a sequential treatment system

Zr-doped nanocrystalline PbO2 (Zr-PbO2) film electrodes were prepared at different bath temperatures. The Zr-PbO2 electrode doped at 75 degrees C (75-Zr-PbO2) featured high oxygen evolution overpotential, large effective area and good electrocatalytic performance. The oxygen evolution potential and the effective area of 75-Zr-PbO2 achieved 1.91 V (vs. SCE) and 9.1 cm(2), respectively. The removal efficiency and the defluorination ratio of PFOA reached 97.0% and 88.1% after 90 min electrolysis. The primary mineralization products (i.e., F- and intermediates) and their change trends were determined. The 75-Zr-PbO2 electrode was introduced to sequentially treat the PFOA wastewater. In an 116 h of 75-Zr-PbO2 electrocatalysis sequential process, the PFOA, PFHpA, PFHxA, PFPeA, PFBA, PFPrA, TFA, and TOC concentrations were reduced to below 30, 2.5, 1.3, 1.0, 0.5, 0.2, 0.1, and 9 mg L-1, respectively, demonstrating the promising application of the sequential treatment system for the treatment of PFOA wastewater. (C) 2016 Elsevier B.V. All rights reserved.