新型二氧化铅电极处理硝基苯废水

Research on the Treatment of Nitrobenzene Wastewater by Electrolysis on a Novel Lead Dioxide Anode

采用高压塑片的方法制备了一种PbO2电极,用X衍射、扫描电镜、火焰原子吸收分光光度法对该电极性能进行了考察,并探讨了该电极降解硝基苯的机理和工艺条件.结果表明,该电极与普通石墨电极相比,CODCr去除率更高,电解5 h CODCr去除率最高可达65%.由于PbO2电极具有较高的析氧电位,在阳极极化下,PbO2电极表面易生成.OH,这是其电解效率高的主要原因.该电极电解硝基苯的最适条件:ρ(硝基苯)为501.5 mg/L,电极间距为3 cm,溶液pH为7.利用该电极处理含磷酸盐和氯离子的硝基苯废水效果尤为突出,但由于阴极的还原作用,电解过程中硝基苯不能被完全氧化.

A novel technology for the preparation of lead dioxide （PbO2） electrode was studied. The test by XRD, SEM and AAS indicated that this electrode had high activity in electrolysis as well as excellent corrosion resistance. The mechanism and process conditions of nitrobenzene degradation using the PbO2 electrode were further studied. Compared to the graphite electrode, the PbO2 electrode had an obviously higher CODer removal rate of 65% after 5 hours of electrolysis. During electrolysis progress, the surface of PbO2 anode is easy to generate hydroxyl radical due to high oxygen over-voltage of PbO2 anode. The best applicable conditions of PbO2 anode for nitrobenzene mass electrolysis are： nitrobenzene mass concentration 501.5 mg/L, electrode gap 3 cm, and solution pH 7. The results showed that the PbO2 electrode had obvious superiority in CODer removal, especially in the system with phosphate or chloride. But the nitrobenzene cannot be completely oxidized in the electrolysis process, due to the reduction action of the cathode.