粉煤灰沸石分子筛负载氧化铈催化剂的制备及其催化燃烧二氯甲烷性能

以发电厂粉煤灰为原料,采用碱融水热法合成了HZSM-5分子筛（FHZSM-5）,用浸渍法负载10%（w）CeO₂制备了CeO₂/FHZSM-5催化剂,用于二氯甲烷的催化燃烧。盐酸浓度为2 mol/L及粉煤灰和NaOH的质量比为1∶1.2时制备的FHZSM-5纯度最高,结晶度最好,用其制备的CeO₂/FHZSM-5催化剂（CFH-1）催化燃烧二氯甲烷的活性最佳,T₉₀和T₅₀（转化率为90%和50%时对应的反应温度）分别为348 ℃和304 ℃,低于其他条件下制备的同系列催化剂。低空速和低二氯甲烷入口浓度更有利于催化燃烧反应的进行。在100 h的连续稳定性测试中,所制备的CFH-1催化剂表现出较高的稳定性,二氯甲烷转化率一直保持在75%以上。

Preparation of fly ash zeolite supported cerium oxide catalyst and its catalytic performance for combustion of dichloromethane

Using fly ash in power plant as raw material,HZSM-5 molecular sieve （FHZSM-5）was synthesized by alkali melting-hydrothermal method,and was loaded with 10%（w）CeO₂ by impregnation method to prepare the CeO₂/FHZSM-5 catalyst for catalytic combustion of dichloromethane （DCM）. When the hydrochloric acid concentration is 2 mol/L and the mass ratio of fly ash to NaOH is 1∶1.2,the prepared FHZSM-5 has the highest purity and the best crystallinity,and the CeO₂/FHZSM-5 catalyst prepared with it （CFH-1）has the best catalytic activity for combustion of methylene chloride. T₉₀ and T₅₀ of CFH-1 are 348 ℃ and 304 ℃,respectively,which are lower than those of the same series of catalysts prepared under other conditions. Low space velocity and low DCM inlet concentration are more favorable for catalytic combustion reaction. In the 100 h continuous stability test,the prepared CFH-1 catalyst shows high stability,and the conversion of CFH-1 to DCM remains above 75%.