Removal Of Toluene Polluted Air By Photoxidation Coupled With Catalytic Oxidation

Toluene was used in interior decoration materials and industrial applications widely, and the air pollution and water pollution problems caused by toluene released into the environment were getting worse and worse. Therefore, it is necessary to deal with the toluene pollution problem. The first purpose of this paper is to set up a system of toluene degradation experiment, such as the selection of light wavelength and the catalyst. The second is to optimize the catalyst, then evaluate its catalytic performance and explore influence of the catalyst on efficiency of toluene in different H2O content and in different regeneration methods. The main content of the article are as follows.1. UV254+185nm was selected as the light wavelength of this system. It was necessary to explore one catalyst which had high catalytic performance in catalytic oxidation of toluene and decomposition of O3. TiO2(P25)/MnOx catalyst which was prepared on foamed nickel substrates by powder sintering technique showed good catalytic activity.2. Effects of Mn/(Ti+Mn) ratio, calcination temperature, H2O content on toluene removal were studied. Proportion and valence state analysis of elements of catalysts was characterized by SEM, EDS spectrum, XRD, XPS. It was found that the removal of toluene by TiO2(P25/MnOx catalysts was listed in the order of X[Mn/(Ti+Mn)=10%]<X[Mn/(Ti+Mn)=20%] >X[Mn/(Ti+Mn)=30%]>X[Mn/(Ti+Mn)=40%]>X[Mn/(Ti+Mn) =60%] in different Mn/(Ti+Mn) ratio. The removal of toluene increased at first and then decreased as Mn loading increased. The removal of toluene by TiO2(P25/MnOx catalysts was listed in the order of X(T=200 ?)< X(T=300 ?)< X(T=400 ?)> X(T=500 ?) in different Calcination temperatures.3. H2O molecules played a promoting role for toluene removal, when its content was low, while a high content of water inhibited the removals of toluene and O3. Comparing XPS patterns of the fresh and used TiO2 (P25) /MnOx catalyst, it was found that Mn2+ generated, which indicated ozone decomposition on manganese oxide catalyst is a metal reduction reaction. Toluene removal of system added TiO2 (P25)/MnOx catalyst is more thorough, more secure than under UV illumination by mineralization experiments and product analysis.The catalyst could not restore its original catalytic properties by 400 ? calcination regeneration and water washing regeneration.