The Modification Of Ti/TiO₂NT/PbO₂ Electrode And Its Degradation Of Organic Wastewater Research

The electro-catalytic oxidation technology as an environment-friendly advanced oxidation technology attracts extensive attention because of its effectiveness in the degradation of bio-refractory organic pollutants, environmental compatibility, little secondary pollution, high security and easy implementation. Ti/PbO2 electrode is widely used as industrial anode due to its low cost, excellent conductivity, excellent corrosion and high electrocatalytic activity. However, the activity and stability of the Ti/PbO2 electrode needs to be improved as more as possible. Therefore, we make a series of fundamental researches in order to improve the activity and stability of Ti/ PbO2 electrode. The main contributions of this research are as follows:The TiO2NT/SnO2-Y interlayer was prepared by thermal decomposition, which improves PbO2 coating structure effectively, and enhances the electrochemical performance of PbO2 electrode. The PbO2-Pr layer was prepared by direct electrodeposition methods. The electrocatalytic performance of the PbO2 electrode was improved by the doping of lanthanide Pr. The SEM and XRD tests show that TiO2NT/SnO2-Y/PbO2-Pr electrodes possess more compact structure, finer grain size and bigger specific surface.A novel Fe and Ce co-doped Ti/TiO2NT/PbO2 electrodes were deposited by two different processes, pulse electrodeposition (P) and direct electrodeposition (D). The SEM, EDS, XRD and XPS tests show that Ti/TiO2NT/Fe-Ce-PbO2 electrodes (P) possess more compact structure and finer grain size than Ti/TiO2NT/Fe-Ce-PbO2 electrodes (D) prepared by direct electrodeposition. The electrochemical measurements show that Ti/TiO2NT/Fe-Ce-PbO2 electrodes (P) have Lower interfacial resistance, higher Oxygen evolution potential and electrocatalytic performance.The best degradation conditions were confirmed by Methylene blue (MB) simulation wastewater degradation experiment. The chemical oxygen demand (COD), organic carbon content (TOC) and ultraviolet-visible absorption spectrophotometer were used to characterize the degradation of MB. The results show that the MB and TOC removal efficiency in 0.2 M Na2SO4 solution containing 50 mg-L-1 MB could achieve 99% and 66% for TiO2NT/SnO2-Y/PbO2-Pr electrodes, respectively, with an applied current density of 70 mA·cm-2 after 150 min.The service lifetime of TiO2NT/SnO2-Y/PbO2-Pr electrodes was 320 h. The MB and COD removal efficiency in 0.2 M Na2SO4 solution containing 30 mg·L-1 MB could achieve 81% and 99% for Fe and Ce co-doped Ti/TiO2NT/PbO2 electrodes, respectively, with an applied current density of 50 mA·cm-2 after 120 min. The accelerated service life experiments indicate that Ti/TiO2NT/Fe-Ce-PbO2 electrodes (P) exhibit excellent stability than Ti/TiO2NT/Fe-Ce-PbO2 electrodes (D). Kinetic analyses indicated that the electrochemical oxidation of methylene blue on the PbO2 electrodes followed pseudo-first-order reaction.