[Infrared study on adsorption of O3 at SnO2 surface]

SnO2 was prepared by precipitation method and mental oxides modified SnO2 catalysts were prepared by coprecipitation method. High concentration molasses fermentation wastewater degradation by SnO2 catalyzed ozonation was used as a probe reaction and IR spectra were used to study the adsorption of O3 at SnO2 and different metal oxides modification SnO2 surface. The results showed, that in the infrared absorption spectra of adsorption of O3 prepared by pure O2 at SnO2 catalyst surface, two obvious bidentate absorption double peaks were found at 1 027 and 1 055 cm(-1), and 2 099 and 2 122 cm(-1), respectively. However, there was competitive adsorption between O3 prepared by air, and CO and CO2. Then the O3 adsorption decreased, leading to the decrease in the degradation of molasses fermentation wastewater by SnO2 catalytic ozonation, and after 60 min reaction, the degradation rate by pure oxygen as oxygen source was 79.2%. It was 33.1% more by air as oxygen source. Similar strength adsorption peaks in the infrared spectra were found at 2 236, 2213 cm(-1) and 1 628, 1 599 cm (-1) with Fe2O3, NiO, CuO, ZnO, MgO, SrO and BaO modified SnO2. But the adsorption of CO2 and CO was different on modifier-SnO2, There was a wide absorption peak at 1 580-1 070 cm(-1) in the infrared spectra of transition metal modified SnO2, and two new peaks at 1 298 and 1 274 cm(-1) were found between 1 580 and 1 070 cm(-1) in the infrared spectra of alkaline-earth metals modified SnO2 catalysts. These changes leaded to a different catalytic ozonation activity of modifier-SnO2, the results of molasses fermentation wastewater degradation by ozone combined with alkaline-earth metal modified SnO2 was obviously better than ozone combined with transition metal modified SnO2. And among them, the ozonation catalytic activity of BaO-SnO2 was the best.