Preparation Of Mn-Based Catalysts And Their Catalytic Performance For Oxygenated Volatile Organic Compounds Oxidation

The oxygenated volatile organic compounds（OVOCs）is one of the important air pollutants,which participates in the formation of photochemical smog and haze and cause great pollution to the environment and serious harm to human body.Catalytic oxidation technology is an effective method to control OVOCs,it has the advantages of simple operation and no secondary pollution.The key lies in the design,development and application of catalytic materials with high activity,high durability and low cost.This paper is aimed at manganese catalysts which has with better oxidation-reduction performance and low price were studied.The performance of manganese based catalysts for oxidation of oxygen-containing volatile organic pollutants at low temperature was improved by changing the preparation method,crystal structure,element composition and loading mode of manganese based catalysts.The main conclusions are as follows:（1）Taking Mn O₂as the research object,first,the catalytic performance of the catalyst prepared by the redox method,hydrothermal method and pyrolysis method was compared,and it was found that the catalyst prepared by the redox method had the highest catalytic activity for acetone;γcrystal form of Mn O₂,it is found that different crystal forms of Mn O₂have different catalytic activity on acetone,of whichα-Mn O₂has the highest catalytic activity on acetone,T_90%is 189°C;Finally,the precursors and reactions during the preparation ofα-Mn O₂The dosage ratio,reaction temperature and reaction time were optimized.（2）The use of transition metal elements Fe,Ni,Cu,Co doped manganese oxide to make bimetallic oxide catalysts,the study found that Fe Mn catalyst has better catalytic activity for OVOCs,found in the process of Fe Mn catalyst doping ratio and roast The temperature has a great influence on the acetone catalytic activity of Fe Mn catalyst.When the Fe addition ratio is 20%and the calcination temperature is 400°C,the T_90%of the catalyst to acetone can reach 173°C,which is attributed to the good oxidation of the catalyst Reducibility,larger specific surface area,more oxygen adsorbed on surface.The catalyst has no obvious change in catalytic activity for 10consecutive tests.It maintains a conversion rate of more than 90%for acetone within85 hours at 180°C.It also has good catalytic effect on n-butyraldehyde and ethyl acetate.（3）Compared with the Mn@SBA-15 supported catalyst prepared by in-situ loading method and impregnation method,it was found that the catalyst prepared by in-situ loading method showed better catalytic performance for OVOCs,in which T_90%of acetone,n-butyraldehyde and ethyl acetate They are 200°C,183°C,and200°C respectively.The characterization test data shows that the catalyst prepared by the in-situ loading method has a higher specific surface area and more surface oxygen adsorption.In addition,the study found that the removal method of the carrier template agent also has a greater impact on the performance of the catalyst,using potassium permanganate oxidation to remove the template agent,while loading the active component manganese oxide on SBA-15 to make Mn/SBA-15 The catalytic performance is excellent,and its acetone T_90%can be as low as 165°C.