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4257874 
Journal Article 
Formation and roles of hydrogen peroxide during soil remediation by direct multi-channel pulsed corona discharge in soil 
Wang, T; Qu, G; Sun, Q; Liang, D; Hu, S 
2015 
1 
Separation and Purification Technology
ISSN: 1383-5866 
147 
17-23 
WOS:000356553300003 
H2O2 is one of the most major active species generated in discharge plasma process. A multi-channel pulsed discharge plasma system was developed to investigate H2O2 formation characteristics during p-nitrophenol (PNP) contaminated soil remediation. Effects of gas varieties (air, O-2, Ar and N-2), air flow rate, and species scavengers on H2O2 formation were evaluated, and PNP degradation performance was also evaluated under various species scavengers. The experimental results revealed that the highest H2O2 concentration was obtained in O-2 plasma atmosphere, and followed in descends by air, Ar and N-2 atmospheres; and H2O2 formation rates in the case of O-2, air, Ar and N-2 were 2.9 x 10(-7), 1.8 x 1.2 x 10(-7) and 8.9 x 10(-8) mol L-1 S-1 under the condition of peak pulse discharge voltage of 27.0 kV and gas flow rate of 0.8 L min(-1), respectively. Increasing air flow rate to a certain extent was beneficial for H2O2 formation. The addition of n-butanol or H2PO4- into soil sample displayed negative effects on H2O2 formation, while the addition of HCO3- promoted H2O2 formation. Direct attack of high energy electrons to water molecules was the main pathway for H2O2 formation during direct pulse discharge plasma in soil; electrolysis reaction route of dissolved O-2 would take place to generate H2O2 and ozone decomposition in alkaline soil also played significant roles in H2O2 formation; however, the recombination of (OH)-O-center dot radicals exhibited relatively low contribution to H2O2 formation. PNP degradation efficiency decreased by 12.7%, 19.0% and 30.4% within 45 min's discharge plasma treatment at 27 kV with n-butanol, HCO3- and H2PO4- addition, respectively, which further confirmed the roles of high energy electrons and (OH)-O-center dot radicals in H2O2 formation. (C) 2015 Elsevier B.V. All rights reserved. 
Pulse discharge; Soil remediation; Hydrogen peroxide; Active species scavenger; p-Nitrophenol