Removal Of Trace Hydrogen Cyanide In Cigarette Smoke By Adsorption And Catalytic Oxidation

Since HCN is a extremely toxic compound, It is extremely harmful to both health and life environment in the waste water, waste gas, etc. It possesses the potential advantage to treat gaseous HCN, especially to remove the HCN in the waste gas producing from smoking, by the catalytic oxidation and adsorption methods. So far there only were some literatures of the adsorption of HCN on activated carbon, and no on other adsorbent. On the other hand, almost all the reports on the removal of HCN were using by the catalytic oxidation method by the noble metals, which resulted in some problems such as the expensive catalysts and high reaction temperature (500-800 癈 ),etc. Consequently, the studies on development of highly effective catalysts, which can be used at lower temperature, are of great importance.In the present thesis, the methods on both analysis and synthesis of HCN, and its removal by the adsorption and catalytic oxidation have been investigated systematically. The main results obtained are as follows:1.The HCN was analyzed using isonicotin acid - babituric acid method and a continuous flow equipment (AA3). This procedure had some advantages such as saving time, the great quantities of the sample dealt with, and short detection period. The working efficiency was therefore improved.2. In order to avoid possible danger caused by HCN in the laboratories, the oxidation reaction was selected to prepare HCN for the use of the catalytic oxidation experiments. The catalysts containing Ce and Mo were prepared to produce HCN by the catalytic oxidation of CH3CN. It was found that the catalytic activity of CeMoxOy(SiO2) (x<5) catalyst, in which SiO2 was used as a support, was the highest among the tested catalysts. The activity of the above catalyst by the addition of V2O5 could be improved further. Both the life and activity stability tests and TG analysis showed that new catalyst had both higher thermal stability and alonger service life.3. The adsorption of HCN on the two adsorbents, Y -Al2O3 and TiO2 , was investigated. The main adsorption of HCN was chemical adsorption, and all the removal rates of HCN were over 90%. The adsorption capacity of HCN on Y -Al2O3 was greater than that on TiO2.4. The catalysts containing transition metal oxides such as CuO/ Y -Al2O3, Ag2O/ Y -Al2O3, Co2O3/ Y -A12O3, CuO/TiO2 and CuO/CeO2 were prepared. The catalytic oxidation reactions of HCN over the catalysts were compared at different conditions. It was found that the catalytic properties of CuO/ Y -A12O3 is the best among the tested catalysts. Both support and the loading level of Cu on it had greater effect the activity of on the catalyst. The catalyst supported with 5%(wt%) of Cu was the most effective for the catalytic oxidation of HCN. The removal rate of HCN by the catalytic oxidation was over 95%. By thermal stability test and TG analysis, It was showed that the catalyst had higher thermal stability.