采用沉淀法制备了SnO2催化剂,以SnO2催化臭氧氧化降解糖蜜酒精废水脱色为探针反应,对催化剂的活性进行了评价.采用X射线衍射、红外光谱及热分析(TG-DSC)等技术对催化剂进行表征,研究了沉淀剂及焙烧温度等制备参数对SnO2催化臭氧氧化活性的影响.结果表明,SnO2催化剂对臭氧氧化降解糖蜜酒精废水脱色具有较高的催化活性,反应60 min后,糖蜜酒精废水的脱色率从单独臭氧氧化的43.04%提高到60.24%.沉淀剂对SnO2催化剂的活性影响很大,其中以氨水为沉淀剂制备的SnO2催化剂去羟基化反应程度高,所制得的催化剂活性最大.催化剂适宜的焙烧温度为723 K.SnO2吸附吡啶的红外光谱表明,催化剂表面存在L酸中心.臭氧在SnO2表面吸附的红外光谱表明,通过臭氧的末端氧原子与表面羟基及L酸中心成键,生成的活性氧可氧化降解糖蜜酒精废水.
Heterogeneous catalytic ozonation technology is a new ozone oxidation method and can degrade organic compounds that cannot be oxidized or degraded by ozone alone at room temperature and normal pressure. A SnO2 catalyst was prepared by the precipitation method and used in decolorization of molasses fermentation wastewater through ozonation. Effects of precipitants and calcination temperature on the catalytic ozonation activity of SnO2 were studied by X-ray diffraction, infrared spectroscopy (IR), and thermal analysis (TG-DSC). The results showed that the SnO2 catalyst exhibited considerably high catalytic activity for the catalytic ozonation decolorization of molasses fermentation wastewater. The decolorization rate of the wastewater was enhanced from 43.04 % (using ozone oxidation alone) to 60.24 %. The activity of the SnO2 catalyst was significantly affected by the precipitants, SnO2 prepared using ammonia as the precipitant showed higher degree of dehydroxylation and higher catalytic activity than those prepared using NaOH and Na2CO3 precipitants. The optimal calcination temperature of SnO2 was 723 K. The IR spectra of adsorbed pyridine showed that there were Lewis acid sites on the surface of the SnO2 catalyst. The IR spectra of O3 adsorbed on SnO2 showed that the terminal O atom of O3 was bonded to the surface hydroxyl group or a Lewis acid site to form a more active oxygen species that can oxidize and degrade the wastewater.