Study On The Characteristics And Application Of UV Induced By Dielectric Barrier Discharge

Dielectric barrier discharge(DBD)is effective to produce low-temperature plasma.During discharge,ultraviolet radiation can be induced.Ultraviolet photons with higher energy could attack and break chemical bonds,resulting in a series of physical and chemical reactions.In recent years,the application of DBD in the treatment of environmental pollution has attracted extensive attention,which has the advantages of mild discharge conditions and thorough treatment of pollutants.However,how to improve the UV radiation efficiency effectively has become an urgent problem.The discharge characteristic is the key factor to determine the ultraviolet radiation efficiency.The results showed that the energy efficiency of DBD driven by pulse is higher than driven by sine.In this paper,through the comparative study of the circuit model,numerical simulation and other discharge characteristics driven by sinusoidal and modulated pulse power supply,combined with experiments,the discharge conditions are optimized to improve the discharge efficiency.In the study of the circuit model,the superiority of the pulsed power supply driving dielectric barrier discharge is explained by the simplified calculation of the equivalent circuit.The generation of secondary discharge is due to the use of the energy of memory charge.Whether the energy can be effectively used is the key factor affecting the efficiency of dielectric barrier discharge.In the study of numerical simulation,dielectric barrier discharge driven by sinusoidal and modulated pulse is simulated.The results showed that different from the sinusoidal dielectric barrier discharge,the modulated pulse can stimulate the secondary discharge,which leads to the multi pulse discharge phenomenon of the discharge current,and switch between glow discharge and Townsend discharge.With the increase of the discharge voltage,the amplitude of the secondary charge increases and the discharge voltage increases.The discharge current amplitude,the air gap voltage drop and the surface charge density are also improved.The decrease of discharge gap,the increase of applied voltage amplitude and the decrease of pulse frequency lead to the increase of current pulse number,and the influence on air gap voltage drop,discharge current density and dielectric surface charge is similar to that of sine.In the experimental study,the effects of discharge characteristics on photolysis were studied by comparing the changes of electrical parameters driven by sinusoidal and modulated pulses,and taking 2,4-D,a typical herbicide in water environment,as the target pollutant.The experimental results showed that the 2,4-D degradation rate of DBD driven by modulated pulse is higher than that driven by sinusoidal pulse;the frequency and duty cycle of modulated pulse directly affect the discharge power and ultraviolet radiation intensity,thus affecting the 2,4-D degradation rate.