Research On Selectively Catalytic Combustion Of Acetonitrile By Transition-Metal Supported SBA-15

As we all know, nitrile gases are the nitrogen-containing volatile organic compounds, which come from the emission of certain chemical plants, such as acrylonitrile plants, organic glass plants and coking plants. If they will be discharged to the outside, they may destroy the ecological balance, and pollute the environment, and cause poisoning to humans and animals. Catalytic combustion is an effective removal method of organic waste, which has a lower ignition temperature, no secondary pollution, recycled heat, simple process and low cost of operation and maintenance. Catalytic combustion has a distinct advantage for dealing with cyanide gases.Mesoporous molecular sieve is a new materials which is a 2-50 nm in diameter and has regular channels distribution, in particular SBA-15 mesoporous molecular sieves has large surface area, regular pore structure, good thermal stability, which has a good prospect in industrial catalysis. In recent years, it becomes the research focus that some transition metals and their oxides will load into the channels of mesoporous molecular sieve to prepare a highly active catalyst.In this paper, we put forward a catalytic removal of acetonitrile coming from the tail gases of acrylonitrile or organic glass plants by meas of mesoporous molecular sieve supporting with the transition metals. A series of catalysts was prepared via an incipient wetness impregnation, and characterized by XRD, N2 adsorption, TEM, H2-TPR and XPS as well as activity test for CH3CN+O2 reaction. Among the monofuctional metal (Cr, Co, Cu and Mn) catalysts with 2% loading amount, Cu/SBA-15 has an ideal catalytic activity and selectivity, in which the highest conversion of acetonitrile is close to 100%, the highest N2 yield is about 80%, CO2 yield can reach 100%, and this performance is better than those of Cr/SBA-15, Co/SBA-15 and Mn/SBA-15. In the bifunctional metal catalyst,2% Cu was selected as the main active component due to its high reactivity for CH3CN selective combustion. In addition,1% of Mn, Co and Ag was loaded as the secondarily active component as well as 4% of Zn, Zr and La was introduced to modify the SBA-15 framework, aiming at achieving a synergistic effect. It was found that the nitrogen yield was significantly improved, but the acetonitrile conversion and carbon dioxide yield would be associated with the essential nature of secondarily loaded metals. The optimal proformance was achieved in the case of Cu-Zr/SBA-15, showing activity superior to Cu/SBA-15 for acetonitrile selective oxidation.