Preparation of RuO2-TiO2/Nano-graphite composite anode for electrochemical degradation of ceftriaxone sodium

Highlights: • RuO₂-TiO₂/Nano-G anode was prepared by sol-gel method and hot-press technology. • Addition of RuO₂ decreased the charge transfer resistance of TiO₂/Nano-G anode. • RuO₂-TiO₂/Nano-G anode displayed high electrochemical degradation performance. • Electrochemical degradation mechanism of RuO₂-TiO₂/Nano-G anode was proposed. • Degradation pathways of ceftriaxone by RuO₂-TiO₂/Nano-G anode were proposed. - Abstract: Graphite-like material is widely used for preparing various electrodes for wastewater treatment. To enhance the electrochemical degradation efficiency of Nano-graphite (Nano-G) anode, RuO₂-TiO₂/Nano-G composite anode was prepared through the sol-gel method and hot-press technology. RuO₂-TiO₂/Nano-G composite was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and N₂ adsorption-desorption. Results showed that RuO₂, TiO₂ and Nano-G were composited successfully, and RuO₂ and TiO₂ nanoparticles were distributed uniformly on the surface of Nano-G sheet. Specific surface area of RuO₂-TiO₂/Nano-G composite was higher than that of TiO₂/Nano-G composite and Nano-G. Electrochemical performances of RuO₂-TiO₂/Nano-G anode were investigated by cyclic voltammetry, electrochemical impedance spectroscopy. RuO₂-TiO₂/Nano-G anode was applied to electrochemical degradation of ceftriaxone. The generation of hydroxyl radical (OH) was measured. Results demonstrated that RuO₂-TiO₂/Nano-G anode displayed enhanced electrochemical degradation efficiency towards ceftriaxone and yield of OH, which is derived from the synergetic effect between RuO₂, TiO₂ and Nano-G, which enhance the specific surface area, improve the electrochemical oxidation activity and lower the charge transfer resistance. Besides, the possible degradation intermediates and pathways of ceftriaxone sodium were identified. This study may provide a viable and promising prospect for RuO₂-TiO₂/Nano-G anode towards effective electrochemical degradation of antibiotics from wastewater.