The important role of the hydroxy ion in phenol removal using pulsed corona discharge

The characteristics of phenol removal by pulsed corona discharge using multi-point-disk electrodes reactor have been investigated to identify the important role of OH− in phenol removal and the degradation mechanism. The removal efficiency of phenol was highest at about 150 rpm of the disk electrode. Decreasing the gap of electrodes or increasing the repetition rate of pulse could benefit to the phenol removal. Reactive species could be produced not only from dissociation of water vapor and O2 but also from N2. The formation of HNO3 mainly resulted in the decrease in pH, and the decrease in pH in return resulted in the decrease of phenol removal rate. The ozone was formed from radical reactions, then diffused into solution and oxidized the phenols. The radicals very near the solution surface could also have the possibility to diffuse into solution and oxidize the phenols in the liquid–gas interface. The basic media could improve the ozone oxidation processes, but the acidic media could worsen them.