School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
Beijing Key Laboratory of Resource-Oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Beijing, 100083, China.
Environ Sci Pollut Res Int. 2018 May;25(15):14471-14485. doi: 10.1007/s11356-018-1657-3. Epub 2018 Mar 10.
Simultaneous oxidation of Hg and NH-SCR of NO by catalyst is one of the key methods for co-purification of coal-fired flue gas. Till now, the interaction between the oxidation of Hg and NH-SCR of NO and its mechanism have not clarified. In this study, a series of nanophase Ce Zr Mn O was prepared for the simultaneous oxidation of Hg and NH-SCR of NO at low temperature. The catalysts were characterized using surface area analysis, X-ray diffraction, temperature-programmed techniques, and several types of microscopy and spectroscopy. The experimental results indicated that the CeZrMnO exhibited superior Hg removal efficiency (> 99%) and NO conversion efficiency (> 90%) even at 150 °C, and it also exhibited a good durability in the presence of SO and HO. The excellent performance of CeZrMnO on co-purifying Hg and NO was due to the stronger synergistic effects of Ce-Zr-Mn in CeZrMnO than that of the others, which was illustrated by the characterization results of XPS, XRD, and FT-IR. Moreover, it was found that the NO conversion of CeZrMnO could be slightly influenced by Hg and was decreased about 4% to the max, while that of Hg could rarely be affected by the selected catalytic reduction process of NO. It might be due to the co-purification mechanism of NO and Hg. The mechanism of the simultaneous oxidation of Hg and NH-SCR of NO was mainly due to the synergetic effect on the mobility of surface oxygen and the activation of lattice oxygen of CeZrMnO. The effect of the oxidation of Hg on the NH-SCR of NO was mainly due to the absorbed Hg/Hg on the surface of CeZrMnO, which attenuated the formation of NH, -NH, and NH on its acid sites. Similarly, the NH-SCR of NO process could hardly influence the oxidation of Hg when NO and Hg were co-purified.
同时氧化 Hg 和 NH-SCR 脱硝是燃煤烟气净化的关键方法之一。到目前为止，Hg 的氧化与 NH-SCR 脱硝之间的相互作用及其机制尚未阐明。在本研究中，制备了一系列纳米相的 CeZrMnO 用于低温下同时氧化 Hg 和 NH-SCR 脱硝。采用比表面积分析、X 射线衍射、程序升温技术以及多种显微镜和光谱学对催化剂进行了表征。实验结果表明，CeZrMnO 即使在 150°C 下也表现出优异的 Hg 去除效率（>99%）和 NO 转化率（>90%），并且在存在 SO 和 HO 的情况下也表现出良好的耐久性。CeZrMnO 在同时净化 Hg 和 NO 方面的优异性能归因于 CeZrMnO 中 Ce-Zr-Mn 的协同作用强于其他催化剂，这通过 XPS、XRD 和 FT-IR 的表征结果得到了说明。此外，发现 CeZrMnO 的 NO 转化率可能会受到 Hg 的轻微影响，最大可降低约 4%，而 Hg 的转化率则很少受到所选 NO 催化还原过程的影响。这可能是由于 NO 和 Hg 的共净化机制所致。Hg 和 NH-SCR 脱硝同时氧化的机理主要归因于 CeZrMnO 表面氧的迁移性和晶格氧的活化的协同作用。Hg 氧化对 NH-SCR 脱硝的影响主要归因于 CeZrMnO 表面吸附的 Hg/Hg，这削弱了 NH 、-NH 和 NH 在其酸性位上的形成。同样，当 NO 和 Hg 同时净化时，NO 的 SCR 过程几乎不会影响 Hg 的氧化。
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