Investigation On The Prepration Of Manganese Oxide Catalyst And Its Catalytic Performance

This paper prepared manganese oxide power by precipitation method and aceticacid combustion method. The manganese oxide crystal structure and microstructurewere characterized by using instrument analysis. By resorcinol degradation experiment,the catalytic oxidation performance of manganese oxide was studied.Preparation of manganese oxide by precipitation method: the manganese oxideprecursor was prepared with ammonia and sodium carbonate as precipitant, respectively.Mn (NO3)2as source of manganese, the manganese oxide catalyst powder was gottenafter roasting4h under550℃in the electric box furnace. Preparation by aceticacid combustion method: the manganese oxide and modified manganese oxide bycerium doping were synthesized with acetic acid as accelerant, Mn (NO3)2and Ce (NO3)3·6H2O as sources of manganese and cerium. Preparation of modified manganese oxidewith loading cerium by impregnation method: different concentration cerium nitrate wasadding into manganese oxide prepared by combustion method, then moved into electricbox furnace after fully grinding, the modified manganese oxide were prepared after4hroasting at550℃.We characterized the manganese oxide and the modified manganese oxide byusing X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric (tg)-differential thermal analysis (DSG-TGA) and Fourier infrared analysis(FTIR). The differences in manganese oxide composition and surface appearance werestudied, prepared under conditions of different precipitants, different cerium doping andcerium loading. Analysised the influence on preparation of catalyst, on the effect ofdifferent mole ratio of nitric acid manganese and amino acetic acid, different calcinationtemperature. The results show that, the compound crystal of mainly Mn2O3crystal,Mn3O4vice is received by precipitation method, with the average particle size of0.5μm.The manganese oxide crystal size: sodium carbonate precipitation is larger thanammonia precipitation. By using amino acetic acid combustion method, the optimumMn3O4catalyst is synthesized on the conditions of nitric acid manganese and aminoacid mole ratio3:8, the calcination temperature at550℃, with a most of hydroxylcontent on the surface. The crystal size enlarged as increase of calcination temperature.Mn3O4and CeO2composite crystal were received`on the preparation of both ceriumdoping and cerium loading modifying. The cerium doping makes a difference on manganese oxide crystalline phase, while the cerium loading has less impact onmanganese oxide crystalline phase. The modified manganese oxide crystal size enlargedwith the amount of both cerium doping and cerium loading increased. The catalyticoxidation performance of manganese oxide was discussed with degradation of resorcinsolution as simulate wastewater. Results indicate that the catalytic oxidationperformance of manganese oxide prepared by sodium carbonate precipitation method isbatter than ammonia precipitation method. The degradation ratio of resorcin oxided bymanganese oxide is greatly strengthened with addition of H2O2. We achieved themodified manganese oxide with best catalytic oxidation performance on resorcin underconditions of nitric acid manganese and amino acid mole ratio3:8, n（Ce）：n（Mn）=3:7, thecalcination temperature at550℃. The degradation rate of resorcin reached50%after60min reaction, under the reaction conditions of catalyst amount1000mg/L, H2O2content tendency for0.15/ml, pH is6~8, natural light.