| At present,various kinds of pollution in the environment have seriously affected people's daily life,while the traditional treatment methods can't achieve the effect of low cost and no secondary pollution.According to the existing research background,plasma technology is widely used in water treatment,waste gas treatment and sterilization.Strong ionization discharge has a good industrial application prospect because of the high ionization degree of gas and strong plasma activity.In order to solve the problem that the energy consumption of strong ionization discharge is still high,the pulse strong ionization discharge technology is proposed.Moreover,it has the advantages of low energy consumption of pulse discharge and strong ionization discharge particle activity,which can improve the discharge efficiency and reduce the power consumption.To achieve the above purpose,a coaxial plasma generator with discharge gap less than 0.3 mm is designed,and a pulsed strong ionization dielectric barrier discharge system is constructed with a self-made pulsed power supply in the laboratory.In this paper,the characteristics of pulsed strong ionization dielectric barrier discharge were analyzed and applied to the treatment of organic wastewater.The main results are as follows:(1)The characteristics and emission spectra of pulsed strong ionization dielectric barrier discharge in He,He+air,He+O2 systems were analyzed and measured.The results show that these gases are typical filamentous discharge.Emission spectrum test shows that they all contain N2+(B-X),N2(C-B),OH(A-X)and other particles.In addition,the generated OH(A-X)and O(IV)have strong oxidation;(2)The effects of the flow rate and the ratio of the working gas on the O3 generation ability of the pulsed strong ionization dielectric barrier discharge were investigated.The experimental results show that the working gas flow rate is 2 L/min,the voltage is in the range of 95?160 V and the gas mixing ratio is 1.5:0.5,the O3 production is the best.The maximum amount of O3 produced by ionizing He+O2 gas is 40.2 mg/L.This is twice the amount of O3 produced by ionizing He+air gas;(3)The treatment of organic dye wastewater by pulsed strong ionization dielectric barrier discharge under different conditions was investigated.The experimental results show that the decolorization rate of organic wastewater increases with the increase of voltage.Under the experimental conditions of gas flow rate of 2 L/min,the He+O2 mixing ratio of 1.5:0.5 and input voltage of 140 V,the treatment effect of organic dye wastewater is the best.The decolorization rate of single organic wastewater can reach 94.68%,and mixed organic wastewater can reach 91.61%;(4)The energy consumption of strong ionization discharge system with different excitation sources was investigated.The experimental results show that the strong ionization discharge excited by pulse power supply is more energy-saving than that excited by high frequency power supply.When the decolorization rate is more than 95%.The optimal discharge energy consumption is only20%of that when excited by high frequency power supply;(5)Due to the narrow discharge gap and high ionization degree,the plasma generator designed in this paper is more likely to form oxygen active particles with high concentration of O2+,O3,O-,O+,O2-.These particles can be used to decompose the chromogenic groups of methylene blue and methyl violet dyes efficiently after they are introduced into the solution,so as to degrade and decolor the organic matter.The discharge gap designed in this paper is less than 0.3 mm,and the stable strong ionization discharge is realized.The electric field intensity of the discharge reaches 33.5 kV/mm,which is three times higher than the traditional discharge.The generator uses self-made pulse power supply as excitation source.The decolorization rate is nearly 95%when it is applied to the treatment of organic dye wastewater.The optimal discharge energy consumption is only 20%of that when excited by high frequency power supply. |
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