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

A novel technology for the preparation of lead dioxide(PbO_2) 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 PbO_2 electrode were further studied.Compared to the graphite electrode,the PbO_2 electrode had an obviously higher COD_Cr removal rate of 65% after 5 hours of electrolysis.During electrolysis progress,the surface of PbO_2 anode is easy to generate hydroxyl radical due to high oxygen over-voltage of PbO_2 anode.The best applicable conditions of PbO_2 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 PbO_2 electrode had obvious superiority in COD_Cr 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.