Chem. J. Chinese Universities ›› 2025, Vol. 46 ›› Issue (8): 20250096.doi: 10.7503/cjcu20250096

• Physical Chemistry • Previous Articles     Next Articles

Electrochemical Removal of PFAS by Boron-doped Diamond Electrode

ZHANG Senchong1,2, LYU Jitao2, WANG Sen1(), LYU Jilei3, WANG Shaolong4, WANG Yawei2,5   

  1. 1.College of Urban and Environmental Sciences,Northwest University,Xi’an 710127,China
    2.State Key Laboratory of Environmental Chemistry and Ecotoxicology,Research Center for Eco?Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China
    3.Hubei Carbon Six Technology Co. Ltd. ,Yichang 443000,China
    4.Tubular Goods Research Institute of China National Petroleum Corporation,Xi’an 710072,China
    5.School of Environment,Hangzhou Institute for Advanced Study,University of Chinese Academy of Sciences,Hangzhou 310024,China
  • Received:2025-04-02 Online:2025-08-10 Published:2025-04-28
  • Contact: WANG Sen E-mail:wangsen@nwu.edu.cn
  • Supported by:
    the Strategic Priority Research Program of the Chinese Academy of Science(XDB0750000);the Research Funds of Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences(2024HIAS-P001)

Abstract:

In this study, six boron-doped diamond(Nb/BDD) electrodes with different boron doping levels were prepared using niobium flakes as the substrate by microwave plasma chemical vapor deposition, and the effects of different boron doping levels on the electrochemical performance of Nb/BDD electrodes and their oxidation of perfluorooctanoic acid(PFOA) were investigated and applied to the electrochemical removal of different perfluorosulfonic acids(PFASs). The results showed that with the increase of boron doping level, the grain size of the Nb/BDD film gradually decreased and the electron transfer rate on the electrode surface gradually increased, but the decrease of film quality leads to the increase of its exfoliation rate. Na2SO4 was used as the electrolyte, and the Nb/BDD electrode as the anode was able to oxidize PFOA within 120 min at a current density of 30 mA/cm2. PFOA degradation rate to 78.3% and mineralization rate to 78.1% within 240 min. Among the six Nb/BDD electrodes prepared with different boron doping levels, the medium and low-doped Nb/BDD electrodes have higher degradation and mineralization ability for PFOA, indicating that the efficient electrochemical removal of PFAS can be achieved by regulating the boron doping level of BDD. The analysis of the degradation products indicated that the electrochemical degradation of PFOA follows the law of carbon chain step-by-step removal, in which the direct electron transfer between the anode and the pollutant is the key initiation step of degradation. The electrochemical degradation of PFSA and perfluorocarboxylic acid(PFCA) with different chain lengths reveals that the length of the carbon chain is positively proportional with the degradation rate and mineralization rate of PFAS, and thus the short-chain products generated by the degradation are the main reason for limiting the complete mineralization of PFAS. In the future, more attention needs to be paid to the efficient removal of short-chain and ultrashort-chain PFAS in order to meet the demand for the complete detoxification of PFAS through electrochemical technologies.

Key words: Perfluorooctanoic compound, Boron-doped diamond electrode, Electrochemical oxidation, New pollution

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