Experimental Study Of Reaction Kinetics On DBD Catalytic Oxidation Of Adsorbed Toluene

Volatile organic compounds?VOCs?are an important part of air pollution,which can harm the environment and human health.Dielectric barrier discharge?DBD?is one of the most popular methods for adsorption storage-plasma catalytic oxidation of VOCs,which has the advantages of uniform discharge,stable process,high energy efficiency and high selectivity.The reaction kinetics of DBD catalytic oxidation of adsorbed VOCs is crucial for the reasonable selection of operating parameters and amplification of the reactors,and is the key to promoting the industrial application of the technology,which no study has been previously reported.In order to carry out in-depth study of reaction kinetics,toluene was selected as the research object,and the effects of the catalyst?carrier type,mixing ratio,active component?and operating parameters?discharge voltage,initial adsorption amount,discharge time?on NTP combined catalytic degradation of adsorbed toluene were investigated.And the kinetic model for NTP combined catalytic degradation of adsorbed toluene was established based on the above research.Firstly,the effects of carrier type and mixing ratio on NTP combined catalytic degradation of adsorbed toluene were investigated.Under the same conditions,13X-Al had larger adsorption penetration,higher mineralization rate?62%?and CO₂ selectivity?90%?,and the least by-products O₃ and N₂O.Considering the adsorption and oxidation properties of the carrier,1:4?13X:?-Al₂O₃?was the optimal mixing ratio of 13X-Al.In addition,the response surface method was used to optimize the operating parameters of NTP combined with 13X-Al?mass ratio 1:4?for degradation of adsorbed toluene,and the variation characteristics of interactions of various variables were obtained,and the operating parameters of degradation process were comprehensively optimized.Secondly,the effects of catalyst active component,discharge voltage and initial adsorption amount on NTP combined catalytic degradation of adsorbed toluene were investigated.Catalyst M/13X?M:Ag,Fe,Cu,Co?was prepared by incipient wetness impregnation method,and characterized by BET,XRD,SEM,H₂-TPR and FT-IR.Compared with other catalysts,Ag/13X-Al had the best adsorption performance(adsorption penetration 8.56 mg·g^-1)and oxidation performance?mineralization rate68%,CO₂ yield 64%?,which was mainly due to its larger BET specific surface area,better redox properties and the formation of?complex bonds between Ag and toluene and CO.With Ag/13X-Al as catalyst,the mineralization rate and CO₂ yield increased with the increase of discharge voltage and the decrease of initial adsorption amount,which was beneficial to the oxidation of adsorbed toluene.Finally,the kinetic model of NTP combined catalytic degradation of adsorbed toluene was established by analyzing the above influencing factors.The classical kinetic analysis method was used to obtain that the reactions all conformed to the pseudo-second-order kinetic model?k·t=1/n-1/n₀?.The overall reaction rate constant k was affected by the type of catalyst carrier,mixing proportion and active component.Using Ag/13X-Al as catalyst,the quantitative relationship between overall reaction rate constant k and discharge power P and the initial adsorption amount n₀ was investigated.The kinetic model of NTP combined catalytic degradation of adsorbed toluene was expressed as:0.0009n₀^-2.402·P·t=1/n-1/n₀,and the reliability of the model was further verified.The establishment of the model provides theoretical guidance for the reasonable selection of operating parameters and the amplification of reactors.