Expreimental Study On Degradation Of Benzene Series By Ce-Modified Mn-Based Activated Carbon Fiber Coupled With Non-Thermal Plasma

With the development of the national economy and the improvement of people’s living standards,the automotive coating industry is booming,and a large amount of volatile organic compounds（VOCs）can be produced in the spray painting process of the automotive coating workshop,among which benzene series are the representative,mainly including benzene,toluene and xylene,seriously endangering the physical and mental health of operators.Due to the advantages of high degradation efficiency and low cost,the non-thermal plasma degradation technology has been extensively studied by scholars at home and abroad in recent years.In this paper,activated carbon fiber（ACF）is used as the carrier,and 5%Mn/ACF,5%Ce/ACF and Mn-Ce（m∶1）/ACF supported catalysts are prepared by the water bath heating method,where 5%is the mass ratio of Mn or Ce loaded on the ACF,m∶1 is the mass ratio of Mn and Ce.SEM,TEM,XRD,XPS characterizations are performed,and the prepared catalysts are used to combined with double dielectric barrier discharge（DDBD）to degrade benzene,toluene and xylene gases volatilized in the simulated painting process.The catalysts characterization results show that there is a strong interaction between CeO₂and Mn₃O₄,which increases the proportion of lattice oxygen(O_lat)of the catalysts.At the same time,the presence of a large amount of Ce³⁺promotes the formation of surface oxygen vacancies and enhances the flow of O_lat.Comparing the degradation efficiency,CO₂selectivity and O₃production of benzene,toluene and xylene gas under different conditions,the results indicate that the degradation efficiency and CO₂selectivity of benzene,toluene and xylene gas have been significantly improved after the introduction of the catalysts.while the amount of O₃produced is significantly reduced.The activities of the Ce-modified Mn-based catalysts are better than that of the two single metal catalysts,and the best cooperative performance is observed in Mn-Ce（5∶1）/ACF catalyst.In the case of degrading benzene,Compared with the condition in only DDBD system,when the specific input energy（SIE）is 373 J/L,the benzene degradation efficiency and CO₂selectivity are increased by 22.3%and 19.7%respectively,while the O₃production dropped by55.3%with the introduction of Mn-Ce（5∶1）/ACF catalyst.In the case of degrading mixed gases of benzene,toluene,and xylene,compared with a only DDBD system,the degradation efficiency of benzene,toluene,and xylene was increased by 27%,7.7%,and 5.6%CO₂selection increased by 10.8%,and O₃production decreased by64.2%.The results show that Ce modified Mn-based activated carbon fiber catalyst can significantly improve the degradation efficiency and CO₂selectivity of benzene,toluene,and xylene when coupled with non-thermal plasma technology,and can effectively inhibit the generation of O₃.The prepared Ce-modified Mn-based catalysts have certain application significance in the study of benzene series degradation by non-thermal plasma.