Study On Removal Of Toluene Waste Gas By Ozone Catalytic Oxidation Combined With Biochemical Treatment

Actinochemistry smog and city haze can be cause by VOCs which have already become a main factor of air pollution,so to manage VOCs is no time to delay.There are a few application values when biotechnology and ozonation technology are used to manage VOCs,but some shortcomings exist.Volatile organic compounds can be removed efficiently when using Co,Mn or Ce as catalyst.However,few researches have been made about mixing thus there metals as a complex catalyst.Meanwhile,few researches have been made about using the combination of catalytic ozonation and biotechnology to manage methylbenzene exhaust gas.In this study,the toluene was used as the representative pollutant of benzene system and VOCs.A series of Co-Mn-Ce-O/γ-Al₂O₃catalysts for catalytic oxidation of toluene by ozone were prepared by dipping method usingγ-Al₂O₃as carrier.And investigated the effects of different preparation conditions on the properties of catalysts.Experimental results show that the toluene removal efficiency for the Co-Mn catalyst was higher than that for the active component of the single element catalyst.The addition of rare earth element Ce as a promoter in Co-Mn catalyst can improve the activity of the catalyst.The optimum ratio of cobalt-manganese-cerium is 1:1.5:0.05,the best cobalt loading is 5%and the calcination time is 5h.The catalytic oxidation activity of the catalyst is the strongest,and the removal rate of toluene can up to 94.44%.The single-factor experimental analysis was used to analyze the catalytic performance of toluene in the experiment,and the effects of the addition amount,reaction temperature and feed ratio of the catalysts were investigated.The experimental results show that the amount of catalyst in the 0.8 g is the best.Besides,toluene with ozone feed ratio of 1000:300,the removal rate of toluene,best within the range of 30-75℃,the removal rate of toluene is proportional to the temperature,can be maintained at between85%and 95%.The reaction mechanism of ozone-catalyzed oxidation of toluene was investigated by in-situ infrared technology and GC-MS.It turns out that the strong oxidative properties of ozone can be used to react with the·OH,which catalyzes the catalyzes the catalytic oxidation of toluene.The results show that when the temperature is 30^oC,the ratio of removing VOCs can reach to 83.96%.The combination of the ozonation of methylbenzene and bioanalysis can make the ratio of methylbenzene exhaust gas up to 99.07%.