Enhanced oxidation potential of Ti/SnO2-Cu electrode for electrochemical degradation of low-concentration ceftazidime in aqueous solution: Performance and degradation pathway.

In order to develop an efficient electrode to remove pharmaceutical and personal care products from wastewater, copper and antimony doped Ti/SnO2 electrode were prepared by thermal decomposition. Electrochemical characterization was undertaken on Ti/SnO2-Cu using cyclic voltammetry and linear sweep voltammetry, indicating an ultra-high 2.1 V of oxygen evolution potential, better stability, and superior corrosion resistance rather than traditional Ti/SnO2-Sb electrode. Competitive degradation experiments showed more efficient removal rate was achieved on Ti/SnO2-Cu electrode, which could remove more than 90% ceftazidime within 60 min. The microstructure and crystal orientation of the modified electrodes were investigated by scanning electron microscopy, which indicated that the crystal of the Ti/SnO2-Cu electrode grew in more porous and uniform condition, covered with closely arranged layers of the coating. X-ray photoelectron spectroscopy and X-ray diffractions suggested that Cu2O was successfully coated on the Ti/SnO2-Cu electrode surface. The operating parameters of electrochemical degradation process were also investigated, including current density, initial concentration, electrode distance, stirring rate and supporting electrolyte. Consequently, the intermediate products of electrochemical degradation were monitored by liquid chromatography-mass spectrometry and a major degradation pathway was proposed.