Degradation Of Toluene By Dielectric Barrier Discharge Plasma

With the rapid development of economy,the problem of air is more and more serious.Volatile organic compounds?VOCs?as one of the atmosphere pollutants,have adverse effects to environment and human health,so the treatment of VOCs is widely studied in recent years.However,traditional VOCs control methods have many restrictions,particularly for treating dilute concentration.Dielectric barrier discharge plasma technology has many advantages,such as uniform stability,high electron density,low energy consumption,portable.The high energy electron and other active particles in the reactor can effectively collide with pollutant molecules,eventually breaking them down into CO₂ and H₂O.At the same time,the synergy of plasma technology combined with catalyst can further promote the degration of VOCs,which provides a new way to the decomposition of VOCs.In this work,toluene was adopted as the target contamination,the removal of toluene was carried in an atmosphere DBD reactor.The effects of reactor parameters,process parameters and the kind of catalysts on the removal of toluene were investigated.The experimental results using DBD reactor showed that increasing the input power appropriately,reducing the gas flow rate and initial concentration could contribute to the degradation of toluene.Moreover,the length and space of discharge can influence the removal of toluene in the same time.When the length and space of discharge is 90 mm and 3.0 mm respectively,the highest removal efficiency was acquired.TiO₂ was the most commen photocatalyst.BaTiO₃ was a typical ferroelectric material,which had the advantages of high dielectric contant and low dielectric loss.Therefore,we prepared TiO₂-BaTiO₃ catalysts filling in the discharge distance.In this way,the existence of BaTiO₃ increasing the intensity of discharge and the formation of electron-hole pairs in TiO₂ improving the abililty of oxidation in the reaction space,which enhanced the removal efficiency,selectivity and energy efficiency.Ti1Ba1catalyst had the highest catalytic performance among them.A series of CeO₂-MnOx catalysts were prepared by sol-gel method,which were placed in the discharge district.All the catalysts were characterized in detail using N₂adsorption,XRD,TEM,H₂-TPR,Raman,O₂-TPD and XPS analysis technology to discuss the structure and performance.The catalytic performance of CeO₂-MnO_x catalysts were higher than pure CeO₂ and MnO_x,which might be contributed to the synergistic effect between CeO₂ and MnO_x(such as Mn³⁺/Mn²⁺and Ce⁴⁺/Ce³⁺redox couples)in the CeO₂-MnO_x catalysts.The highest removal efficiency of toluene?95.94%?and CO₂ selectivity?90.73%?were acquired with Ce1Mn1 catalyst.On the basis of the analytic results of GC-MS,the pathways of toluene destruction in the plasma-catalysis system were discussed.