Study On The Degradation Of Methyl Orange Simulated Wastewater By Dielectric Barrier Discharge/Photocatalysis United Use

At present, with the rapid development of society and economy，waterpollution is becoming more and more serious in our country. Emission ofindustrial wastewater is one of the causes of water pollution， especiallyprinting and dyeing industry，is the major emitters of water pollution. Printingand dyeing wastewater has many characteristics such as deep chromaticity, highemissions, complicated water quality, great toxicity, high COD，it not only isharmful to humans，but also can threaten the survival of other species.Therefore,control and deal with printing and dyeing wastewater has become an importantand imminent task.In recent years，there are a lot of new water treatment technologies，plasmatechnology has been widely used because it is a combination of high energyelectron bombardment，chemical oxidation and UV irradiation. However, it isreported that ultraviolet light in the plasma discharge process can not be made full use of，energy utilization is low. So this paper combines DBD plasma withcommercial P-25to deal with methyl orange simulated printing and dyeingwastewater.This experiment adopts self-made column cylinder dielectric barrierdischarge reactor and consists of three parts：separately use DBD plasma todegrade methyl orange；DBD plasma combines with powder P-25to degrademethyl orange； DBD plasma combines with immobilized P-25to degrademethyl orange.In the degradation of methyl orange by using DBD plasma alone, weinvestigated the effect of input power, initial concentration of methyl orange,initial pH value, aeration rate, gas flow ratio (O2:Ar)and reaction time. The bestparameters conditions suggest: initial concentration of methyl orange is100mg/L, aeration rate is150mL/min, input power is30W, reaction time is10min, gas flow ratio (O2:Ar) is2:1,the degradation rate of methyl orange canreach71.1%.In the degradation of methyl orange by using DBD plasma and powderP-25, the results show that: the best dosage of powder type P-25is1.5g/L, thebest calcination temperature of powder type P-25is450℃, the best calcinationtime of powder type P-25is2h, the degradation rate of methyl orange can reach85.7%.The immobilized type P-25was prepared using Na2SiO3as binder andAl2O3as carrier. In the degradation of methyl orange by using DBD plasma and immobilized type P-25, we found that the best number of coating is3times, thebest mass fraction of sodium silicate is20%, the degradation rate of methylorange can reach93.4%.This paper also has carried out the repeated experiment of immobilizedtype P-25, the results show that the degradation rate can still reach71.1%afterusing5times, Therefore，compared with powder type P-25, immobilized typeP-25has better catalytic activity and industrial application value.Finally, this experiment has a preliminary discussion on the degradationmechanism of methyl orange by using DBD plasma and immobilized type P-25,the experimental results show that pH and COD of methyl orange has beendegraded well, and fell to3.5and53mg/L respectively.