SO2和NO在Na-γ-Al2O3上吸附行为的研究

利用吸附曲线和漫反射红外光谱（DRIFTS）研究了150 ℃SO2和NO在Na-γ-Al2O3上的吸附行为。吸附实验在固定床反应器内进行，原料气体积组成为NO (0.1％)、 SO2 (0.51％)、O2 (4.5％)、Ar平衡。研究表明，150 ℃不论气相中是否有氧，Na-γ-Al2O3均能单独吸附SO2或NO，Na-γ-Al2O3单独吸附SO2时，观察不到有SO42-生成，Na-γ- Al2O3单独吸附NO时，NO吸附量较少，有微量NO2（或表面硝酸盐）生成；Na-γ- Al2O3均能同时吸附SO2和NO，SO2和NO在Na-γ- Al2O3上吸附时相互作用，NO促进SO2氧化生成SO42-，SO2吸附量增加，SO2促进NO氧化转化，SO2也促使NO2脱附。气相氧促进了SO2和NO在Na-γ- Al2O3上的吸附以及SO2和NO的相互作用。

Investigation into adsorption behavior of SO2 and NO on Na-γ-Al2O3

The adsorption behavior of SO2 and NO on Na-γ- Al2O3, a sorbent used for simultaneous removal of SOx (98.0%~99.0% SO2) and NOx (90%~99% NO) form flue gas, was investigated in an atmospheric fixed bed reactor at 150 ℃ by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The volumetric composition of feed gas was 0.51% SO2, 0.1% NO, 4.5% O2, Ar as balance. For the adsorption behavior of a single pollutant, SO2 is adsorbed easily and no SO2 is oxidized to form SO42- (at least SO42- can not be detected on the surface of sorbent), whereas NO is adsorbed more difficultly compared with SO2. The adsorption capacity of NO is low, and a small amount of NO2 or surface nitrate is formed. The adsorption capacities of SO2 and NO are improved in the presence of O2. NO and SO2 can be adsorbed simultaneously in the presence or absence of O2. There are interactions between SO2 and NO on Na-γ- Al2O3. The presence of NO favors adsorption of SO2 and formation of SO42-. Whereas effect of SO2 on adsorption of NO is complicated. SO2 can promote NO oxidation to form NO2 or surface nitrate; on the other hand, SO2 can result in desorption of NO2. The adsorption capacities as well as interactions of NO and SO2 are enhanced by O2.