Utilizing natural minerals to remove Hg from flue gas was regarded as a preferable route to control mercury pollution. This paper purposed a novel microwave (MW)-boosted removal method using natural low-grade pyrolusite (NLP), by which over 85 % of Hg was removed and approximately 10–20 % of the increment of efficiency was obtained. Compared with thermo-catalysis, MW also empowered NLP with a wider active-temperature range (100–250 °C) and better HO and SO resistances. Kinetic analysis showed that MW increased the rate constant and reduced the activation energy, Hg-TPD and material balance analyses demonstrated that major Hg was chemisorbed as HgO. Via the thermal treatment experiments, the regeneration performance of NLP was confirmed to be good. From the experiments and characterizations, the mechanism was preliminarily speculated: (i) the contribution order of the active components was MnO > MnO > FeO; (ii) the redox pairs of Fe(II)/Fe(III) and Mn(III)/Mn(IV), as well as the O-species, involved in the conversion from Hg to HgO. Density functional theory calculations revealed the pathway and mechanism: (i) MnO exhibited higher oxidation activity, whereas MnO showed higher adsorption activity; (ii) O derived from O enhanced the removal of Hg by increasing the adsorption energies and amounts of transferred electron; (iii) O had advantages over O in term of desorbing HgO, which was the rate-determining step.

中文翻译：

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使用天然低品位软锰矿进行微波促进元素汞去除


利用天然矿物质去除烟气中的汞被认为是控制汞污染的优选途径。本文提出了一种利用天然低品位软锰矿（NLP）的新型微波（MW）增强去除方法，去除了 85% 以上的汞，并获得了约 10-20% 的效率增量。与热催化相比，MW还赋予NLP更宽的活性温度范围（100-250°C）以及更好的H2O和SO2抵抗能力。动力学分析表明，MW 增加了速率常数并降低了活化能，Hg-TPD 和物质平衡分析表明，主要的 Hg 以 HgO 的形式被化学吸附。通过热处理实验，证实NLP的再生性能良好。通过实验和表征，初步推测其机理：（i）活性组分的贡献顺序为MnO> MnO> FeO； (ii) Fe(II)/Fe(III) 和 Mn(III)/Mn(IV) 的氧化还原对，以及 O 物种，参与从 Hg 到 HgO 的转化。密度泛函理论计算揭示了这一途径和机制：（i）MnO表现出更高的氧化活性，而MnO表现出更高的吸附活性； (ii) 来自 O 的 O 通过增加吸附能和转移电子量来增强汞的去除； (iii) O 在解吸 HgO 方面比 O 有优势，解吸 HgO 是速率决定步骤。