AgMn/HZSM-5催化剂上室温O3氧化脱除空气中的苯：Mn含量和水含量的影响

摘要

The effects of Mn loading and water content on AgMn/HZSM-5 (AgMn/HZ) catalysts were investi-gated in the ozone catalytic oxidation (OZCO) of benzene in a continuous air flow at room tempera-ture. The catalytic activity is closely related to the Mn loading, and the AgMn/HZ catalyst with 2.4 wt%Mn (AgMn/HZ(2.4)) had the highest activity and stability in benzene oxidation as a result of its large surface area and high MnOx dispersion. Temperature-programmed desorption of the used catalysts demonstrated that 2.4 wt%was also the optimal Mn loading for suppressing the accumu-lation of benzene and HCOOH over the catalyst surface after benzene oxidation. For AgMn/HZ cata-lysts with Mn loadings≤2.4 wt%, O3 decomposition to active oxygen species (O*) plays the most important role in benzene oxidation;however, benzene activation is the crucial step for benzene oxidation by O3 over AgMn/HZ catalysts with Mn loadings>2.4 wt%. The AgMn/HZ(2.4) catalyst was then used to perform OZCO of benzene in a humid stream. Compared with dry gas, water vapor greatly enhanced the activity and stability of the AgMn/HZ(2.4) catalyst, and 0.1-0.2 vol%was the optimal water content for benzene oxidation.%考察了Mn含量和水含量对AgMn/HZSM-5(AgMn/HZ)催化剂上室温O3氧化(OZCO)脱除空气中苯的影响.研究发现, Mn含量为2.4 wt%的AgMn/HZ催化剂(AgMn/HZ(2.4))具有大的比表面积和高的MnOx分散度, OZCO活性和稳定性最高.反应后的程序升温脱附结果表明,2.4 wt%的Mn含量能有效抑制苯和甲酸在催化剂上的残留.当Mn含量≤2.4 wt%时,催化剂分解O3的活性在苯氧化过程中占主导；当Mn含量>2.4 wt%时,苯的活化起主要作用.基于AgMn/HZ(2.4)催化剂优越的反应活性和稳定性,进一步研究了湿气流中该催化剂上苯的氧化.与干气流相比,水汽的加入能显著提高催化剂的反应活性和稳定性,且以0.1-0.2 vol%水含量时最优.