Mercury pollution is created by coal combustion processes in multi-component systems. Adsorbent injection was identified as a potential strategy for capturing Hg⁰ from waste gases, with adsorbents serving as the primary component. The hydrothermal approach was used to synthesize a series of MnO_x–CeO_x nanorod adsorbents with varying Mn/Ce molar ratios to maximize the Hg⁰ capture capabilities. Virgin CeO_x had weak Hg⁰ elimination activity; <8% Hg⁰ removal efficiency was obtained from 150 °C to 250 °C. With the addition of MnO_x, the amount of surface acid sites and the relative concentration of Mn⁴⁺ increased. This ensured the sufficient adsorption and oxidation of Hg⁰ while overcoming the limitations of restricted adsorbate-adsorbent interactions caused by the lower surface area, endowing MnO_x–CeO_x with increased Hg⁰ removal capacity. When the molar ratio of Mn/Ce reached 6/4, the adsorbent’s Hg⁰ removal efficiency remained over 92% at 150 °C and 200 °C. As the molar ratio of Mn/Ce grew, the adsorbent’s Hg⁰ elimination capacity declined due to decreased surface area, weakened acidity, and decreased activity of Mn⁴⁺; <75% Hg⁰ removal efficiency was reached between 150 °C and 250 °C for virgin MnO_x. Throughout the overall Hg⁰ elimination reactions, Mn⁴⁺ and O_α were in charge of oxidizing Hg⁰ to HgO, with Ce⁴⁺ acting as a promoter to aid in the regeneration of Mn⁴⁺. Because of its limited adaptability to flue gas components, further optimization of the MnO_x–CeO_x nanorod adsorbent is required.

Graphical abstract

中文翻译：

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MnOx-CeOx纳米棒吸附剂消除Hg0能力的机理研究：Mn/Ce摩尔比的影响

汞污染是由多组分系统中的煤炭燃烧过程产生的。吸附剂注入被认为是从废气中捕获 Hg ⁰的潜在策略，其中吸附剂是主要成分。采用水热法合成了一系列具有不同Mn/Ce摩尔比的MnO _x –CeO _x^{纳米棒吸附剂，以最大限度地提高Hg 0}捕获能力。原始CeO _x具有弱的Hg ⁰消除活性；从 150 °C 到 250 °C，获得了<8% Hg ^{0去除效率。}_{随着MnO x}的添加，表面酸位点的数量和Mn ⁴⁺的相对浓度增加。^{这确保了Hg 0}的充分吸附和氧化，同时克服了表面积较低导致的吸附质-吸附剂相互作用受限的限制，赋予MnO _x –CeO _x增加的Hg ⁰去除能力。当Mn/Ce摩尔比达到6/4时，吸附剂在150℃和200℃下对Hg ^{0的去除率均保持在92%以上。}随着Mn/Ce摩尔比的增大，吸附剂表面积减小，酸性减弱，Mn ^{4+活性降低，去除Hg 0}能力下降；_{对于原始 MnO x ，}在 150 °C 至 250 °C 之间达到<75% Hg ⁰去除效率。在整个Hg ⁰消除反应中，Mn ⁴⁺和O _α负责将Hg ⁰氧化为HgO，Ce ^{4+充当促进剂以帮助Mn 4+}的再生。_{由于MnO x} –CeO _x纳米棒吸附剂对烟气成分的适应性有限，需要进一步优化。

图形概要