摘要
采用高压塑片法制备了纯PbO2电极及掺杂锰矿粉的PbO2复合电极，通过扫描电镜、加速寿命测试对电极性能进行了考察，并探讨了用PbO2复合电极对弱酸性桃红BS溶液进行的电催化降解机制和工艺条件。结果表明，PbO2复合电极的使用寿命是纯PbO2电极的3．3倍；在所考察的范围内，随着电流密度的增大，染料转化率和COD去除率均随之增加，当电流密度由70mA／cm^2增加到90mA／cm^2时，染料转化率和COD去除率增加趋势减缓；溶液pH对染料降解有影响，弱酸性桃红BS溶液在强酸和强碱条件下的降解效果较好，pH在3．98～7，99时，染料转化率和COD去除率变化不大；染料转化率和COD去除率均随着电解时间呈递增关系，3．0h后上升趋势逐渐减缓；支持电解质为NaCl时，能使染料转化率迅速提高，但其COD去除率不是很高；支持电解质为KNO3时，能显著提高弱酸性桃红BS溶液的COD去除率，0．5h时COD去除率达到83％以上。另外，通过加入羟自由基清除剂叔丁醇的研究表明，在弱酸性桃红BS的降解过程中，有羟自由基产生并参与了催化降解反应。
The pure PbO2 electrode and the composite PbOz-MnO2 electrode, modified by adding powder manganese mineral （75 % MnO2, Mn powder）, were prepared by the high pressure molding method. The electrode properties were evaluated by SEM, the accelerated life testing and the relative effectiveness of treating a synthetic peach color wastewater was compared. The service life of the composite electrode was 3.3 time that of the pure PbO2 electrode. The composite electrode also was more effective in treating the wastewater （30 mg/L of BS, pH=3.00） with higher removal rates for both color and COD. Operating at the best treatment conditions （Mn powder content： 17.6%, pH：2.48, reaction time ：3.0 h, and current density=70 mA/cm^2 ） and using nitrate as the electrolyte, 83% COD reduction was achieved in 0.5 h. The electrochemical oxidation activity of PbO2 electrode was improved by the addition of Mn pow- der. Hydroxyl was formed on the electrode and participated in the oxidation of the organic substance.
出处
《环境污染与防治》
CAS
CSCD
北大核心
2008年第7期16-20,23,共6页
Environmental Pollution & Control
基金
国家自然科学基金资助项目(No.50379003)
江苏省环境工程重点实验室开放基金资助项目(No.060710E2)
合肥工业大学校基金资助项目(No.070701F)
关键词
电化学氧化
锰矿粉
高压塑片PbO2电极
electrochemical oxidation
manganese mineral
high pressure molding
PbO2 electrode
