Mechanism of enhanced electrochemical degradation of highly concentrated aspirin wastewater using a rare earth La-Y co-doped PbO2 electrode

A novel La-Y-PbO2 electrode was prepared by electrodeposition technique and the degradation mechanism for aspirin was explored. In contrast with the PbO2 electrode, La-PbO2 electrode and Y-PbO2 electrode, La-Y-PbO2 electrode displayed a more compact surface with a smaller grain size of crystal, accompanying with increased concentration of active oxygen species. The higher voltammetric charge quantity of La-Y-PbO2 electrode indicated its larger electrochemical active surface area and higher electrochemical activity. The La-Y-PbO2 electrode was demonstrated to have a superior electrochemical oxidation ability, which had a higher apparent rate constant, mass transport and mineralization current efficiency and lower energy consumption. The evolution of intermediates and the aspirin degradation mechanism were further discussed. Meanwhile, high reusability and safety were achieved by La-Y-PbO2 electrode when treating aspirin wastewater. (C) 2015 Elsevier Ltd. All rights reserved.