Degradation of Sulfamethazine by Ni-Doped Lead Dioxide Electrode in Electrocatalytic Ozonation Process

An Ni-doped PbO2 electrode (Ti/TNAs/Ni-PbO2) with titanium dioxide nanotube arrays (TNAs) self-growth on the titanium metal surface as an intermediate layer was prepared by electrodeposition. Characterization and electrochemical testing of the Ti/TNAs/Ni-PbO2 showed a denser surface structure, a larger surface active area (0.50 m2 g-1), and smaller crystallite size (38.61 nm), which provided more surface active sites and promoted the generation of hydroxyl radicals (•OH). The electrocatalytic ozonation process was established using the electrode. The sulfamethazine (SMT) was selected as the target contaminant. The performance on SMT removal in electrocatalytic ozonation was systematically evaluated. The effects of initial SMT concentration, current density, electrolyte concentration, initial pH, and ozone dosage on the degradation rate of SMT and chemical oxygen demand (COD) removal were also investigated. Under optimal conditions, after 60 min of degradation, the removal rates of SMT and COD reached 100% and 46.13%, respectively. Intermediates in the degradation process were identified by ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry, and the degradation mechanism and degradation pathways of the Ti/TNAs/Ni-PbO2 anode in the electrocatalytic ozonation process were explored. The excellent efficacy and stability of this anode in this process were verified and showed a potential for widespread application in highly concentrated organic wastewater treatment