Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, China; Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, China.
J Hazard Mater. 2019 Jul 15;374:267-275. doi: 10.1016/j.jhazmat.2019.04.006. Epub 2019 Apr 3.
Manganese oxides with different crystallographic structures were investigated for gas-phase elemental mercury removal. The inherent thermal regeneration performance and mechanism of α- and γ-MnO were studied. The manganese dioxides were found to possess a mercury removal efficiency of higher than 96% even after 120 min mercury exposure except for β-MnO which removed much less mercury than MnO. The α-MnO was found to have a higher recyclability of mercury capture and better durability for regeneration than γ-MnO. During the first 1 h of exposure, α-MnO showed an excellent mercury capacity of 128 μg/g over 5 regeneration cycles. While for γ-MnO, the mercury capacity of the fifth cycle was reduced to 68.74 μg/g, which is much lower than 131.42 μg/g for the first cycle. The microstructure of α-MnO was maintained throughout regeneration cycles due to its capability to retain lattice oxygen. In comparison, γ-MnO experienced reconstruction and phase transformation induced by oxygen vacancies due to lattice oxygen loss during regeneration process, leading to a degradation in mercury capture. The α-MnO oriented composite was found to be better developed into a regenerable catalytic sorbent for mercury removal from flue gases of coal-fired power plants.
研究了不同晶型结构的氧化锰用于气相元素汞的去除。研究了α-和γ-MnO 的固有热再生性能和机制。结果发现，除了β-MnO 外，其他两种二氧化锰在 120 分钟的汞暴露后，都具有高于 96%的汞去除效率，而 MnO 则去除了较少的汞。与 γ-MnO 相比，α-MnO 具有更高的汞捕获可循环性和更好的再生耐久性。在暴露的前 1 小时内，α-MnO 在 5 次再生循环中表现出了 128μg/g 的优异汞容量。相比之下，γ-MnO 在第五次循环中的汞容量降低到 68.74μg/g，远低于第一次循环的 131.42μg/g。由于α-MnO 能够保留晶格氧，因此其微观结构在整个再生循环中得以保持。相比之下，γ-MnO 在再生过程中由于晶格氧的损失而经历了氧空位引起的重构和相变，导致汞捕获能力下降。α-MnO 定向复合材料被发现更适合开发为从燃煤电厂烟气中去除汞的可再生催化吸附剂。
