Research On Dielectric Barrier Discharge Cooperative Catalytic Treatment Of VOCs

Recent studies on the treatment of VOCs with dielectric barrier discharge（DBD）co-catalyst showed that VOCs are important participants in the formation of atmospheric haze and photochemical smog.These air pollution are harmful to environmental safety and human health.The traditional VOCs control methods tend to deal with high concentration of VOCs,and it is limited by the defects such as high construction cost and high operating and maintenance cost at the beginning of the period,so it can not be popularized in a large area.On the one hand,the dielectric barrier discharge（DBD）combined with catalyst can improve the treatment efficiency and selectivity of the target product,on the other hand,it can reduce the production of by-products in the treatment of VOCs by dielectric barrier discharge（DBD）,so it has great application value.In this paper,the dielectric barrier discharge（DBD）device is used to treat VOCs with transition metal oxide catalyst.The main results are as follows:（1）The discharge power of single and double dielectric barrier discharge devices,the treatment efficiency of three kinds of VOCs and the energy efficiency of the device are studied.The main conclusions are as follows:aromatic hydrocarbons are more difficult to degradate than halogenated hydrocarbons and ester compounds.The energy efficiency of the double dielectric barrier discharge reactor is lower than the single one,but it’s comprehensive removal effect is better,the higher output voltage can improve the degradation rate of VOCs and the energy efficiency of the reaction system.However,the improvement of energy efficiency is limited.The comprehensive removal effect is better when deal with lower concentration of VOCs,and the optimum concentration is obtained at relatively high voltage when taking into account the energy efficiency and degradation rate.（2）During the process of dielectric barrier discharge（DBD）treatment of VOCs,the by-product NOx is produced.In this paper,the production of NO under different conditions has been studied by DBD-catalyst（transition metal oxide（Mn、Co、Ce）on Al₂O₃）system.The main conclusions are as follows:the concentration of NO increases with the increase of energy density;the type of catalyst and discharge power affect the production of NO;NO is partially involved in the reaction with CO、NH、NH₂ and so on.When increasing the initial concentration,the amount of intermediate products can be increased,thus the consumption of NO can be increased.However,The control of energy density is the most important control methd of nitrogen oxides.（3）adding MnOx/Al₂O₃ which has the best effect of controlling NO into the reactor to treat the toluene:adding catalyst in the second half of the discharge region of the dielectric barrier reactor,It can achieve high removal rate and mineralization degree for low concentration of toluene,and the by-product NO can also be controlled on specific energy density.（4）the tail gas treated by the reactor is detected by GC-MS and FTIR.The composition of the product and the influence of different catalyst at different energy density are compared.The final products are CO₂ and H₂O,and the intermediate by-products include alcohols,aldehydes,acids,NOx and amines,DBD reactor can promote the further oxidation of VOCs in the range of energy density when combine with catalyst.