Modification Of Titanium-based PbO₂ Electrode And Electrochemical Degradation Of Doxycycline Hydrochloride

Doxycycline hydrochloride（DOX）,a widely used broad-spectrum antibiotic,was used in large quantities and its residues in the environment caused a series of environmental problems.In this study,small amounts of bismuth（Bi）and cerium（Ce）were co-doped in the titanium matrix lead dioxide anode（Ti/PbO₂）using the electro-deposition method.Scanning electron microscopy（SEM）,X-ray diffraction（XRD）,and X-ray photoelectron spectroscopy（XPS）were used for the characterization of the electrodes.And the prepared PbO₂anode was found to be mainly composed ofβ-PbO₂,and Ti/PbO₂/Bi-Ce 03（co-doped with 0.5 mmol/L Bi and0.5 mmol/L Ce in PbO₂anodes）had the best catalytic effect and surface structure.Compared with Ti/PbO₂,doping improved its corrosion potential（21.8%）,accelerated lifetime（108.3%）,and degradation efficiency（43.6%）while reducing the electrochemical impedance（17.91%）.It was proved by a single-factor experiment that the degradation rate of DOX was 100%at 10min with a current density of 10 m A/cm²,electrolyte concentration[Na₂SO₄]=0.1 mol/L,and p H=4.In addition,the degradation of DOX fitted the first-order kinetic equation.The DOX degradation on Ti/PbO₂/Bi-Ce 03 electrode was mainly attributed to direct oxidation and SO₄^·-.Four possible degradation pathways were postulated using the results of high-performance liquid chromatography-mass spectrometry（HPLC-Ms）.Using quantitative structure-activity relationship（QSAR）,the acute and developmental toxicity of DOX and the individual intermediates were examined,and the majority of them still retained high ecotoxicity.However,after 6 hours of electrochemical anodic oxidation of doxycycline hydrochloride,the reaction system’s overall acute toxicity was significantly decreased.The thesis provided a new way for preparing Ti/PbO₂electrodes with high catalytic activity and longer lifetime,and also an efficient way for degradation of antibiotic DOX.