| Toluene is a kind of typical Volatile Organic Compounds?VOCs?.Traditional methods like absorption have many problems like complex equipment,while plasma technology has great potential in the field of air pollution control due to its high degradation efficiency,short reaction time and simple operation.Revealing the influence law of parameters on degrading toluene with plasmasynergized adsorption further,reasonably controlling the reaction process,identifying intermediate products are hot issues in current research.Based on these above,this paper carried out an experimental study on the adsorption and removal of toluene by dielectric barrier discharge plasma coexisting with carbon nanotubes,and discussed the effects of low-temperature plasma power supply parameters,initial pollutant concentration,complex mixing atmosphere and other factors on the removal efficiency.The main contents are as follows:Firstly,the research progress of toluene degradation technology is reviewed.The advantages and disadvantages of several typical VOCs dealing technologies and plasma discharge category are hold up and compared.Technology of low-temperature plasma used in adsorption was introduced,and the properties of carbon nanotubes and two kinds of dielectric barrier discharge plasma?DBD?purification experiment system were introduced in detail too.In system of degrading and removing toluene by single dielectric barrier discharge plasma,the effects of the power parameters,initial concentration of toluene were researched through the experimental.The experimental results show that an increase in the output power will improve the efficiency of toluene removal.The removal efficiency of toluene raised from basically 0 to a maximum value of80%when the output power changed from 1k W to 3.2k W.When the initial concentration of toluene increased from 120mg/m3to 800mg/m3,the removal efficiency of toluene decreased from 78%to 66%at the time of 30s.The experimental results in complex mixing gases show that the effects of NO and SO2on toluene removal fluctuate,but not significantly.The addition of O2increased the strong oxidizing substances?O·,O3?that were conducive to the decomposition of toluene,which increased from 72%when oxygen content was 0.5%to 83%when oxygen content was 5.5%.The presence of H2O decreased the removal of toluene,the removal efficiency is only 60%at a humidity of 18.5 mg/L,decreased30%compared with that in dry air,according to the Arrhenius law,H2O reacts with O·,O2,·OH is easier to occur and continue than that of H2O degrading into·OH due to the chemical reaction rate constant of the former is less than that of the latter.This article analyzed the gas phase product by mass spectrum analyses,and solid coke by Fourier infrared spectrum analysis to further clarify the possible reaction paths,found that the gas phase during content in addition to large amounts of CO2,still contain benzene ring opening reaction of long chain hydrocarbon,and little aromatic compounds;Solid phase coke products are mainly alcohols and phenols,alkane,alkynes,amine compounds,benzene ring substituents and other incomplete decomposition products.Lastly,in the system of plasma synergized with carbon nanotubes,the structure and adsorption properties of carbon nanotubes has carried on the simple overview,research is mainly focused on the influence of supply power and carbon nanotube placed in wire-tube reactor import on toluene removal,and EDS characterization analysis of carbon nanotubes was involved,and the effects on toluene removal of carbon nanotubes treated by homemade plate DBD plasma reactor was carried out.The results showed that the adsorption efficiency of carbon nanotubes was significantly improved compared with that of the single plasma to remove toluene and the single carbon nanotubes to adsorb toluene.EDS characterization analysis of carbon nanotubes of initial samples,after separate toluene adsorption,after low temperature plasma synergized adsorption was carried out and the results show that the content of element O in the carbon nanotubes after the synergized low-temperature plasma adsorption decreased 2%compared with the original sample.After plate plasma reactor treatment,the removal efficiency of toluene by carbon nanotubes reached more than 50%in a short time,which is 20%higher than that of carbon nanotubes used alone,indicating that plasma irradiation has enhanced its adsorption capacity.The work in this paper not only helps to reveal the mechanism of toluene degradation and removal by low temperature plasma,but also is expected to promote the practical application of carbon nanotubes cooperative adsorption and oxidation technology in industrial VOCs treatment. |
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