The Degradation Of Methyl Orange By Dbd Plasma

This paper had studied the degradation effect of methyl orange by dielectric barrier discharge plasma, analysised the active species generated by dielectric barrier discharge plasma and the role of the active species in degradation process, and detected intermediates of methyl orange degradation and analysised internal mechanism of the degradation of methyl orange solution by dielectric barrier discharge plasma.1,Methyl orange of 100 mg/L was degradated by dielectric barrier discharge plasma at 22.0 kV, 10.5 kHz, normal temperature and pressure. The degradation rate of methyl orange is 60 % for 10 min. The degradation rate of methyl orange is 96.8 % for 30 min and TOC degradation rate is 30.4 % while COD degradation rate is 45.2 %. For 35 min there is no characteristic absorption peak of methyl orange in UV-visible spectrophotometry spectra. And methyl orange had been completely degradated. And the reaction solution is clear and transparent.2,During dielectric barrier discharge degradating methyl orange, it has worse degradation rate of methyl orange if conductivity is higher. And the degradation rate of methyl orange under acidic conditions is significantly higher than neutral and alkaline. SO₄^2- and CO₃^2- will reduce the degradation rate of methyl orange while the Cl^- and Fe²⁺ will increase the degradation rate of methyl orange.3,There are O₃, O₂, OH⁺, N₂, H_α, H₂O⁺, OH and so on producted by dielectric barrier discharge when detected the active species emission spectra in the gas phase. And this paper had analysised level transition of those active species and the degradation law in process of degradating methyl orange.4,It had analysised the ozone generation process and the mechanism of self- decomposition in dielectric barrier discharge. The maximum ozone concentration is 0.231 mmol/L in the liquid phase with water as the discharge medium and the maximum ozone concentration is 0.15 mmol/L with methyl orange as discharge medium. And it had also analysised the physical absorption process and chemical absorption process of ozone.It enhanced chemical absorption process that ozone transfers to the main liquid phase from gas phase.5,The degradation process of methyl orange molecules can be divided into open epoxidation, deep oxidation, and completely degradation three stages by detecting the product of methyl orange and analysising molecular structure of the bond energy and the stages are grouped according to the size of methyl orange molecular bond energy. Speculating reaction mechanism shows that the active species plays an important role in the reaction of molecular dissociation and the oxidation of the benzene rings.