Catalytic Degradation Of Gaseous Styrene By Dielectric Barrier Discharge Combined With Modified Natural Pyrite

In this paper,natural pyrite（Pyr）was used as a carrier,respectively loaded with NiO,ZnO and Co₃O₄ to prepare NiO/Pyr,ZnO/Pyr and Co₃O₄/Pyr composite catalysts.Combined with selfmade dielectric barrier discharge（DBD）reactor,the DBD-catalytic degradation of odor-contaminated styrene was investigated.The prepared catalysts were characterized by various methods,including X-ray diffractometer,specific surface area analyzer,scanning electron microscope,and X-ray photoelectron spectrometer.The catalytic performance of different catalysts was investigated.The effects of initial concentration of gaseous styrene,input power,and gas flow rate on catalytic degradation were analyzed.The reaction process was discussed reasonably with the qualitative results of degradation products.The results showed that:The NiO/Pyr catalyst was prepared by the impregnation method.And the composite catalyst prepared when the mass ratio of NiO to Pyr was 0.2 and the calcination temperature was 500 ^oC showed the best catalytic effect.At an input power of 80 W,an initial styrene concentration of 240 mg m^-3,and a gas flow rate of1.1 m³ h^-1,the removal rate of styrene in the DBD/NiO/Pyr system was increased by10.5%,the energy yield increased by 0.5 g（k Wh）^-1,the mineralization rate increased by 9.5%,the ozone concentration decreased by 63.1%,and the nitrogen dioxide concentration decreased by 19.2%,respectively,compared to the bare DBD treatment.A small amount of coking deposit was generated after a longtime reaction of bare DBD,and the addition of NiO/Pyr catalyst significantly reduced the generation of the coking material.The main components of benzaldehyde,phenylacetaldehyde,acetophenone,benzoic acid,phenylacetic acid,styrene oxide,phenol,nitrophenol,etc.were detected by FT-IR and GC-MC.The ZnO/Pyr catalyst was prepared by the sol-gel method.The catalyst obtained when the mass ratio of ZnO to Pyr was 0.4 and the calcination temperature was 500^oC had the most significant effect on the degradation of styrene.At an input power of80 W,an initial styrene concentration of 240 mg m^-3,and a gas flow rate of 1.5 m³ h^-1,the degradation efficiency of styrene in the DBD/ZnO/Pyr system was increased by16.7%compared to the DBD bare treatment.And the energy yield increased by 0.82g（k Wh）^-1,the mineralization rate increased by about 10%,the ozone concentration decreased by 53.7%,and the nitrogen dioxide concentration decreased by 41.9%.The Co₃O₄/Pyr catalyst was prepared by the impregnation method.The catalyst prepared when the mass ratio of Co₃O₄/Pyr was 0.3 and the calcination temperature was 500 ^oC had the best catalytic activity.At an input power of 80 W,an initial styrene concentration of 240 mg m^-3,and a gas flow rate of 1.5 m³ h^-1,compared with the bare DBD system,the degradation efficiency of styrene in the DBD/Co₃O₄/Pyr system increased by 14.1%,the energy yield increased by 0.64 g（k Wh）^-1,the mineralization rate increased by 8.5%,the ozone concentration decreased by 58.5%,and the nitrogen dioxide concentration decreased by 37.1%.