Degradation Of Organic Compounds In Wastewater By Active Species Sprayed In A Gas Phase Dielectric Barrier Discharge System

In this paper, degradation of organic compounds by active species sprayed in a gas phase dielectric barrier corona discharge system was studied. Two types of reactor, including wire-tube dielectric barrier discharge and surface discharge, were provided for degradation of phenol. Some influencing factors of the technology and the corresponding reasons were investigated, which are expected to provide the reference for further research and industrialization. The main results are summarized as follows:1. Both the reactors exhibited good performances in degradation of phenol. The degradation rate was improved with the increasing input voltage and power frequency. The bubbling gas with oxygen was better than air for degradation of phenol. Solution conductivity had little influence on degradation. The alkaline condition was beneficial for degradation compared with acidic condition. High initial concentration of phenol led to low degradation rate but high energy utilization.2. When wire-tube dielectric barrier discharge reactor was used to degrade 1000 mL phenol solution with an initial concentration of 50 mg/L under the condition of 11.5 kV input voltage, 50 Hz power frequency, 1.6 L/min air flow rate, 10μS/cm and 7 pH value, phenol degradation rate reached to 90% in 60 min.3. When surface discharge reactor was used to degrade 300 mL phenol solution with an initial concentration of 100 mg/L under the condition of 13.1 kV input voltage, 50 Hz power frequency, 1 L/min oxygen flow rate, 100μS/cm and 7 pH value, phenol degradation rate reached to 90% in 30 min.4. Surface discharge combined with TiO₂ photocatalysis to improve the degradation rate was achieved accordingly. Under the condition of 11.6 kV input voltage, 200 Hz power frequency, 1 L/min oxygen flow rate, 100μS/cm and 7 pH value, the degradation rate of 300 mL phenol solution with an initial concentration of 100 mg/L was improved by 13% in 10 min. The mineralization efficiency of phenol in the plasma photocatalysis system was higher than that in the plasma alone system according to the analysis results of byproducts concentration.