Treatment Of Organic Acid Waste Liquid By Dielectric Barrier Discharge

As the advantages of low temperature plasma in the treatment of contaminants have become apparent,the application and the way of generation are being paid more and more attention.The low temperature plasma produced by gas discharge,including high energy electrons and low energy heavy particles,in addition,a large amount of active particles.These particles have high activation energy and react with the reactants to be treated to produce new non-toxicand harmless substances.Therefore,its one of the hot topics in the world to produce available low temperature plasma by gas discharge at atmospheric pressure.This paper explores the current research progress in dielectric barrier discharge both at home and abroad,conducts experiments and studies on the plasma,and has some understanding and cognition of its production mode,properties and applications.Also the discharge structure,discharge mode,discharge mechanism and influencing factors and other aspects are analyzed.A set of waste water treatment system was built with dielectric barrier discharge,and in order to process the waste liquid from the atomization power supply adopts high voltage pulse power supply in the system;the reaction tube electrode is plate electrode;dielectric adopts the perspex materials.Different voltage amplitude and frequency were provided by the pulse power supply to provide the energy for the gas and liquid in the dielectric barrier pipe at the same time.Then large areas of uniform micro discharge happened,and it produced a large number of electronic and active particles to treat the liquid waste.The influences such as pulse voltage amplitude,pulse repetition rate,discharge power and thickness of dielectric plate on the treatment effect of waste liquid are analyzed.Setting pulse voltage amplitude as variable and fixing other parameters unchanged,it is found that when the amplitude of the pulse voltage increases from 4k V to 7k V,the PH of the waste liquid increases from 3 to 4.6.With the increase of pulse voltage amplitude,the energy of single pulse injection increases,the characteristics of gas discharge are more obvious,and the effect of waste liquid treatment is better.When setting the pulse repetition rate is variable,fixed the other parameters unchanged,the increase of pulse repetition rate will not affect the single pulse energy,but it will increase the number of discharge per unit time,the number of high-energy electrons and active particles,thus improving the treatment effect of waste water.When the repetition rate of pulse increases from 50 Hz to 200 Hz,the PH change of waste liquid is about 1.2.The discharge power is an important parameter for characterization of gas discharge,but the measurement of the discharge power is difficult,Lissajous graphical method can be used to obtain the discharge power in this paper,discharge pulse voltage amplitude is higher,the greater the discharge power,the faster the pulse repetition rate,he greater the discharge power,the better treatment effect of waste water.When the fixed voltage amplitude and frequency are fixed,it is found that the smaller the thickness of dielectric plate,the better the treatment effect.The strength of the applied electric field in the gap in the higher,more prone to discharge,and the thickness of dielectric plate directly affects the electric field applied to the power supply gap.The smaller the thickness of dielectric plate is,the higher the electric field intensity in the air gap is,which is more conducive to the discharge.The greater the output of high-energy electrons and active particles,the better the effect of waste liquid treatment.In the experiment,three media with thickness of 1mm,1.5mm and 2mm are obtained.When the external application voltage is 7k V,the difference of PH is about 0.5 between 1mm and 2mm.Using the variation of the effluent PH value as a reference,proved that the discharge plasma(high energy electron,ion and all kinds of active particles)can effectively deal with organic waste liquid,discharge the better the results,the plasma volume,the greater the processing effect is better.