Visible light-driven photoelectrocatalysis for simultaneous removal of oxytetracycline and Cu (II) based on plasmonic Bi/Bi2O3/TiO2 nanotubes

A visible light-driven photoelectrocatalytic system was constructed based on Bi/Bi2O3/TiO2 nanotubes (NTs) to treat wastewater containing oxytetracycline and Cu2+ mixed pollutants. The surface morphology, crystal phase, elemental composition, light absorption property and photoelectrochemical activity of the synthesized Bi/Bi2O3/TiO2 NTs were investigated. The composite film, Bi/Bi2O3/TiO2 NTs was used for the photoelectrochemical removal of oxytetracycline, and it had excellent visible light photoelectrocatalytic performance. Under optimal conditions, the composite film was simultaneously used to remove coexisting oxytetracycline-Cu2+. The study results show that the reduction of Cu2+ on cathode was promoted by oxytetracycline while the degradation of oxytetracycline on photoanode was slightly suppressed by Cu2+. Also, possible photoelectrocatalytic degradation pathways for oxytetracycline-Cu2+ were analyzed by HPLC-MS.