Preparation of CeO2-ZrO2 and titanium dioxide coated carbon nanotube electrode for electrochemical degradation of ceftazidime from aqueous solution

摘要

Carbon nanotubes are extensively used in energy, catalysis and environmental fields because of large specific area and superior electrochemical performances. A novel CeO2-ZrO2/TiO2/CNT anode was fabricated through sol-gel method to improve electrochemical degradation efficiency towards trace pollutant in water environment, such as ceftazidime. Surface structure and elemental compositions were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. A uniform and compact loading of CeO2-ZrO2 and TiO2 nanoparticles were observed which is regarded to be beneficial for stability and catalytic improvement. The optimal loading amount of TiO2 and CeO2-ZrO2 was decided by electrochemical performance and the results indicated addition of 6 mL tetrabutyl orthotitanate in 0.5 g CNT and 3.33% atomic ratio of CeO2/C resulted in a highest removal rate of 83.47% under 3 mA.cm(-2). Cyclic voltammograms, electrochemical impedance spectroscopy and hydroxyl generation test were conducted, demonstrating this anode displayed superior electrochemical properties with greater yield of center dot OH and lower charge transfer resistance. Moreover, kinetic parameters were optimized in this study, indicating an electrode distance of 2 cm and stirring rate of 400 rad.min(-1) were the optimal operation condition from the perspectives of energy consumption and degradation efficiency. Finally, the degradation intermediates and pathways are proposed with HPLC-MS.