The photocatalytic degradation of several organic compounds in airstreams was studied at room temperature by using a bed reactor packed with the commercial HZSM-5 and operated in a circulating mode. It was found that ...The photocatalytic degradation of several organic compounds in airstreams was studied at room temperature by using a bed reactor packed with the commercial HZSM-5 and operated in a circulating mode. It was found that the raw HZSM-5 shows an unanticipated photocatalytic activity for oxidating ethylene, bromomethane and methyl orange. XRF and AAS analyses reveal that the photocatalytic activity of the ZSM-5 results from the trace amount of iron impurity in the sample, and the photoactivity is positively related with the content of iron. The primary results of characterization by XRD, DRS, XPS and SPVS suggest that the most of Fe existed in the framework of zeolite and in a tetrahedral coordination. The iron species might be excited by UV irradiation to form a charge transfer excited complex along with the ligands and an electron excited state of Fe 3+, which are responsible for the photocatalytic behavior of zeolites.展开更多
A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acid...A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO 2- 4/TiO 2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO 2, leading to the obvious increase on photocatalytic activity of SO 2- 4/TiO 2 SiO 2 catalysts and mineralization ratio of bromomethane. Comparing with SO 2- 4/TiO 2, the acidic strength and anti moisture ability of SO 2- 4/TiO 2 SiO 2 catalyst were decreased.展开更多
文摘The photocatalytic degradation of several organic compounds in airstreams was studied at room temperature by using a bed reactor packed with the commercial HZSM-5 and operated in a circulating mode. It was found that the raw HZSM-5 shows an unanticipated photocatalytic activity for oxidating ethylene, bromomethane and methyl orange. XRF and AAS analyses reveal that the photocatalytic activity of the ZSM-5 results from the trace amount of iron impurity in the sample, and the photoactivity is positively related with the content of iron. The primary results of characterization by XRD, DRS, XPS and SPVS suggest that the most of Fe existed in the framework of zeolite and in a tetrahedral coordination. The iron species might be excited by UV irradiation to form a charge transfer excited complex along with the ligands and an electron excited state of Fe 3+, which are responsible for the photocatalytic behavior of zeolites.
文摘A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO 2- 4/TiO 2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO 2, leading to the obvious increase on photocatalytic activity of SO 2- 4/TiO 2 SiO 2 catalysts and mineralization ratio of bromomethane. Comparing with SO 2- 4/TiO 2, the acidic strength and anti moisture ability of SO 2- 4/TiO 2 SiO 2 catalyst were decreased.
