A dielectric barrier discharge (DBD) reactor is introduced to generate H 2 O 2 by non-thermal plasma with a mixture of oxygen and water mist produced by an ultrasonic atomizer. The results of our experiment show that the energy yield and concentration of the generated H 2 O 2 in the pulsed discharge are much higher than that in AC discharge, due to its high energy efficiency and low heating effect. Micron-sized liquid droplets produced by an ultrasonic atomizer in water mist have large specific surface area, which greatly reduces mass transfer resistance between hydroxyl radicals and water liquids, leading to higher energy yield and H 2 O 2 concentration than in our previous research. The influence of applied voltage, discharge frequency, and environmental temperature on the generated H 2 O 2 is discussed in detail from the viewpoint of the DBD mechanism. The H 2 O 2 concentration of 30 mg l −1 , with the energy yield of 2 g kW −1 h −1 is obtained by pulsed discharge in our research.

Dielectric barrier discharge (DBD) is utilized to decompose xylene vapor in mobile gas under normal atmospheric pressure. The plasma is generated by an AC power source with a frequency of 6 kHz. In the experiment, the discharge power on the DBD reactor was calculated by a Lissajous figure, and the specific input energy (SIE) of different discharge voltage or residence time was obtained. The concentrations of xylene, carbon monoxide and carbon dioxide in the gas were analyzed by gas chromatography. The spectra of DBD were diagnosed using a spectrometer. We calculated the conversion rate (CR), mineralization rate (MR) and carbon dioxide selectivity. The relationship between these quantities and the SIE was analyzed. The experimental results show that high concentration xylene can be decomposed mostly by DBD plasma. The CR can reach as high as 90% with the main product of carbon dioxide.

Abstract:Textile dyes are some of the most refractory organic compounds in the environment due to their complex and various structure. An integrated resin adsorption/Dielectric Barrier Discharge (DBD) plasma regeneration was proposed to treat the indigo carmine solution. It is the first time to report ectopic regeneration of the saturated resins by non-thermal Dielectric Barrier Discharge. The adsorption/desorption efficiency, surface functional groups, structural properties, regeneration efficiency, and the intermediate products between gas and liquid phase before and after treatment were investigated. The results showed that DBD plasma could maintain the efficient adsorption performance of resins while degrading the indigo carmine adsorbed by resins. The degradation rate of indigo carmine reached 88% and the regeneration efficiency (RE) can be maintained above 85% after multi-successive regeneration cycles. The indigo carmine contaminants were decomposed by a variety of reactive radicals leading to fracture of exocyclic C=C bond, which could cause decoloration of dye solution. Based on above results, a possible degradation pathway for the indigo carmine by resin adsorption/DBD plasma treatment was proposed.

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