Study On The Removal Of Toluene By Dielectric Barrier Discharge And Catalyst

Toluene is the typical representative of volatile organic compounds(VOCs)and it does harm to human and environment.Plasma is considered to be a good method to remove VOCs.Dielectric barrier discharge(DBD)is widely studied because of its uniform discharge and wide applicability.This paper mainly investigates the toluene degradation in DBD reactor when catalyst is presence and absence.The main research contents and results are as follows:Study on the treatment of toluene by changing reactor structure,electrical parameters and gas parameters is investigated.The results show that there is an optimum value of the discharge diameter and best discharge length.In this experiment,the optimal external diameter of discharge electrode is 1mm and the best discharge length is 8cm.The removal of toluene,CO2 mineralization ratio and NO concentration increase with increasing discharge voltage.However,the O3 concentration increases with the enhance in initial discharge voltage and peaks at 7kV.The removal of toluene and CO2 mineralization ratio firstly increase and then decrease with increasing frequency and peak at 10kHz.Toluene removal and CO2 mineralization ratio decrease with increasing inlet concentration and air flow.The selectivity of catalyst carrier is investigated.It is found that removal capacity of toluene and CO2 mineralization ratio in descending order are:Mn/TiO2>Mn/ZSM-5>TiO2>Mn/Al2O3>Al2O3>ZSM-5.Mn/Ti02 is the best catalyst.When Mn/TiO2 is presence and the voltage is 6.8 kV,the removal of toluene,CO2 mineralization ratio,and O3 concentration are 98.3%,37.95%,0,respectively.Some influence factors on the treatment of toluene are investigated,such as calcination temperature,the amount of active component and the different position of the catalyst.It is found that removal capacity of toluene firstly increases and peaks when the ratio of Mn is 10%and then decreases with increasing amount of Mn.The best calcination temperature is 500? because the content of Mn4+ and the oxidation capacity are best.The effects of different position of the catalyst on the removal of toluene in descending order are:light area>discharge area>cold hydrazine area.The stability of the catalyst is tested.The removal of toluene decreases from 93.9%to 84.1%after 11 days.The reason for catalyst deactivation is the accumulation of organic products on the catalyst such as benzaldehyde and benzoic acid.In addition,the content of Mn4+ decreases from 60%to 44.8%.