矾土尾矿载体双活性组分甲苯催化燃烧催化性能研究

On the toluene catalytic combustion performance of the catalysts with double-active components assisted by bauxite tailings

利用矾土尾矿制备催化剂载体,采用浸渍法将双活性组分氧化物载于催化剂载体,研究甲苯催化燃烧性能。结果表明,当Cu、Mn物质的量比为1∶2、负载量为14%、焙烧温度为500℃、焙烧2 h时Cu Mn/Zr O2整体催化剂催化活性高,起燃温度为210℃,完全燃烧温度为230℃,有效降低了甲苯催化燃烧的起燃温度和完全燃烧温度。

This paper intends to focus its study on the catalytic performance of a kind of metal oxide catalyst in the catalytic combustion of toluene,which is considered to be a toxic chemical for human health and our living environment. As a matter of fact,it is crucial for the said catalytic combustion to prepare appropriate catalyst,in order to decrease the initiation combustion temperature（ at which the conversion rate of toluene is 50%） and the complete combustion temperature（ at which the conversion rate of toluene is 98%）,respectively. Moreover,so far as we know,the catalytic combustion has been used as the commonest method for treating toluene. What is more,the catalysts containing proper amount of the double-active components supported on bauxite tailings are usually prepared by the impregnation method,in which it is necessary to choose the oxides of Cu and Mn appropriately as the double-active components. It is just to obtain the lowest initial total combustion temperatures and proper preparation conditions that we have done experiments in our detailed investigation,such as the on-loading amount,the calcination temperature,the calcination time and the proper ratio of different oxides in the catalyst.In addition,it is also necessary to prepare a kind of aqueous solution with two different kinds of nitrates impregnated on the carrier and then to be heated till it gets to be dry. And,next,it would be possible to obtain the desirable catalyst through repeated impregnation treatment and calcination. Thus,everything having been done,it also needed to conduct the catalytic combustion of the toluene obtained in a tube furnace reactor by taking air as the carrier in a reaction temperature range between from 200 ℃ to300 ℃. When the catalytic combustion of the toluene is over,the process can be expected to be ceased automatically. Finally,we have also checked the conversion rate of toluene via the gas chromatograph,and then examined the microstructure and phase composition of the products which have been obtained via the X-ray diffraction（ XRD） and scanning electron microscopy（ SEM）,respectively. The results of the activity tests we have done indicate that through the calcination test,it is hoped to achieve the greatest activity for the toluene catalytic combustion at the temperature of 500 ℃ for 2 h,at a percentage of 14% of CuM n / ZrO 2（ the molar ratio of Cu to Mn being 1： 2）,whereas the lowest initiation and complete combustion temperature were 210 ℃ and 230 ℃,respectively.