Catalytic Oxidation Of VOCs Over Manganese Oxide Catalysts In Printing/Spraying Industry

Catalytic oxidation is one of the most effective methods for abatement of volatile organic compounds?VOCs?.Manganese oxides are widely used as catalyst because they are highly active,and have a certain ability to resist chlorine poisoning in the catalytic oxidation of CVOCs.In this paper,the catalytic oxidation of benzene and1,2-dichloroethane was studied over single manganese oxide catalysts with different crystalline forms,and the relationship of structure-activity was discussed.The catalytic oxidation mechanism of benzene was also investigated by in-situ FTIR experiment.In addition,the effect of different preparation methods on the catalytic oxidation performance of Mn-Ce composite oxide catalysts was studied.On the basis,high dispersion of composite manganese oxide catalysts doped with different elements were prepared,and their ability to resist chlorine poisoning was emphatically investigated.The main conclusions were as follows:?1?Among the three crystal shapes of single manganese oxide catalysts?Mn₂O₃,Mn₃O₄ and?-Mn O₂?,?-Mn O₂ exhibited the best catalytic oxidation performance,which could be associated with large specific surface area,abundant high valence of Mn and surface oxygen species,and excellent low-temperature reducibility.The single manganese oxide catalysts had a strong catalytic oxidation ability for benzene,and the oxidation ability increases with the increase of manganese valence state.Besides,the catalytic oxidation mechanism of the three crystal shapes of single manganese oxides on benzene might be the same,including the process of attacking benzene ring,destroying benzene ring,forming intermediates and oxidizing intermediates.And the intermediate products were mainly phenolate,aldehyde,maleate,and acetate species.?2?The catalytic oxidation of benzene and 1,2-DCE over Mn-Ce composite oxides prepared by the hydrolysis driving redox co-precipitation and co-precipitation showed,the catalyst prepared by the hydrolysis driving redox co-precipitation had larger pore diameter and specific surface area,abundant crystal defects and surface oxygen species,and excellent low-temperature reducibility,so it exhibited the best catalytic oxidation performance.?3?The high dispersion of binary composite manganese oxide catalysts doped with different elements were prepared by the hydrolysis driving redox co-precipitation,which the Mn-Sn composite oxide catalysts exhibited the best catalytic oxidation performance for benzene,1,2-DCE,vinyl chloride and chlorobenzene.The research work provided experimental and theoretical basis for improving the catalytic oxidation performance of manganese oxide catalysts.