Study on Emission Spectrum of Radicals in Remediation System of Polluted Soil with Pulsed Discharge Plasma in Oxygen.

Based on the advantage of spectroscopy method and the significant effect of ·OH and ·O in advanced oxidation degradation system, the change of relative emission spectra intensities of the ·OH and the ·O in a pulsed discharge plasma (PDP) system bubbled with oxygen were tested by using the spectrum detecting technique in this research. The PDP system with needle-to-net electrode was set up in the paper to remediate the polluted soil. The relative emission spectra intensities of the ·OH and the ·O formed in the PDP system with oxygen (O2) bubbling were detected with the spectrograph to illustrate the critical effect of the ·OH and the ·O on the organic compound degradation in the PDP system. The changes of the relative emission spectra intensities of the ·OH and the ·O under the conditions of without soil addition, with the original soil addition, with the organic compound polluted soil addition and with the organic compound-heavy metal polluted soil addition were firstly investigated in the paper. The effect of peak pulse voltage, electrode gap and O2 flow rate on the relative emission spectra intensities of the ·OH and the ·O were also studied to explain the changing rule of the active species in the PDP system. The obtained results show that the addition of soil are beneficial to the formation of the ·OH and the ·O in PDP system for the soil remediation. The relative emission spectra intensities of the ·OH and the ·O in the PDP system with organic compounds polluted soil addition were lower than those in the PDP system with the original soil addition, which proved the oxidation of the ·OH and the ·O on the organic compounds degradation in the remediation system, and the addition of heavy metal ions were favorable to the degradation of the organic compounds in the PDP system. Furthermore, the increase of the peak pulse voltage as well as theO2 flow rate was in favor of the formation of the ·OH and the ·O, while the relative emission spectra intensities of the ·OH and the ·O were lower under the condition of the higher electrode gap, which demonstrated that the higher electrode gap were not in favor of the active species formation. In the study, based on the description of the pivotal role of ·OH and the ·O in the PDP system for the polluted soil remediation, the influence rule of the main factors during the process of polluted soil remediation in the PDP system on the content of ·OH and the ·O were analyzed. This research will provide some basic experimental evidence for the application of PDP technology on the polluted soil remediation.