Solar Light-Driven Photoelectrocatalytic System for Efficient Degradation of Tetracycline with Simultaneous Removal of Pb(II)

The development of a highly efficient and energy-saving method for simultaneous removal of organic and heavy metal ion mixed pollutants is of great significance. In the present work, a solar-driven photoelectrocatalytic device coupling a plasmonic Ag/AgCl/TiO2 nanotube photoanode and a Ti foil cathode was investigated for effective degradation of tetracycline (TC)-Pb(II) mixed pollutants. The cooperation of plasmonic Ag/AgCl nanoparticles with TiO2 nanotubes significantly increased the light absorption in the visible region and promoted the migration of photogenerated carriers. Under light irradiation, TC was eliminated by reactive oxygen species on the photoanode, while Pb(II) was facilely electrodeposited on the Ti foil cathode. When the proposed device was operated under natural solar irradiation, the degradation efficiency of TC and Pb(II) reached 90.0 and 97.5%, respectively, after 2 h of photoelectrocatalytic treatment. By using HPLC-MS, we identified the intermediate products produced during the degradation process, and tentative degradation pathways were also proposed.