Degradation Of Pollutants By Gas-phase Dielectric Barrier Discharge

With the rapid population growth,modern industrialization,agricultural activities and geological environment,the quality of our water resources is exponentially deteriorating.As the major pollutants,organic compounds in wastewater are of great concern worldwide due to their severe impacts on the environment and human health.Thus,in the case of unavoidable pollutant emissions,wastewater must be treated to up to the strict water quality standards before being discharged into the aquatic ecosystem.Traditional wastewater treatment technology can not meet the needs of current process anymore.Dielectric barrier discharge is a kind of advanced oxidation technique which combines the advantages of ozonation,UV radiation and pyrolysis,it provides new research direction for wastewater treatment.In this paper,a self-designed dielectric barrier discharge device was used to study the generation of hydrogen peroxide and ozone by DBD discharge.The influence of different conditions on the active particles was investigated,and acid red 73 was used as the simulated dyeing for degradation.Taking the results of small-scale experiments as a reference,a set of large-volume water treatment device was designed.The main research contents and conclusions are as follows:(1)The average energy efficiency of hydrogen peroxide produced in the distilled water by small-scale reactor was 0.052 g/kWh.With the energy density increasing,ozone increased first and then decreased.The pH of 3.45 favored the formation of hydrogen peroxide,while The pH of 10.45 favored the formation of ozone.(2)The results of small-scale reactor showed the acid red 73 can be effectively decomposed by plasma.The moderate increase of energy density can increase the degradation ratio.When the energy density was 265.8 kJ/L,the degradation ratio was 70.01%and energy efficiency was up to 2.84 mg/kWh.The excessive energy density would lead to a substantial increase in the temperature of the solution,which was bad for the survival of active particles(such as H2O2 and O3),and caused declining of the energy efficiency.(3)The kinetics of degradation of acid red 73 by DBD was studied macroscopically.It was found that the concentration of acid red 73 in the solution showed an exponentially decreasing trend under different experimental conditions such as mass concentration,pH,discharge frequency and peak voltage.(4)A large-volume water treatment device was designed to handle 60 L tap water.When the power of the reactor was about 2200 W,the average energy efficiency of generating hydrogen peroxide was 0.08 g/kWh.