Preparation and electrochemical treatment application of Ce-PbO 2 /ZrO 2 composite electrode in the degradation of acridine orange by electrochemical advanced oxidation process.

Novel Ce-PbO2 /ZrO2 composite electrodes were successfully fabricated in lead nitrate solution containing cerium ions and ZrO2 particles by composite electrodeposition method. SEM images and XRD results indicated that Ce-PbO2 /ZrO2 composite electrodes have compact structure and fine grain size. Ce-PbO2 /ZrO2 composite electrode has higher oxygen evolution overpotential and stability than Ce-PbO2 electrode. The service life of Ce-PbO2 /ZrO2 composite electrode reaches 318 h, which is 4.2 times as that of Ce-PbO2 electrodes (74 h). The novel Ce-PbO2 /ZrO2 composite electrode was employed as anode to decontaminate acridine orange (AO) by electrochemical oxidization methods. The effect of initial concentration of AO, current density, and initial pH values on the removal ratio of AO were analyzed. The results showed that AO could be completely removed after 90 min electrolysis under the optimal condition: initial AO concentration was 30 mg L-1 , current density was 50 mA cm-2 , and the initial pH value was 5.0. Moreover, the possible degradation pathway of AO was elucidated based on the identification of stable byproducts generated during the electrochemical degradation process by HPLC-MS, which revealed that AO and its byproducts could be effectively eliminated and mineralized into CO2 , H2 O, ammonium and nitrate ions.