Effect of characteristics of KI-impregnated activated carbon and flue gas components on Hg-0 removal
Effect of characteristics of KI-impregnated activated carbon and flue gas components on Hg-0 removal
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KI浸渍活性炭特性和烟气组分对Hg-0去除的影响
DOI：
10.1016/j.fuel.2016.12.083
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发表时间：
2017
期刊：
影响因子：
7.4
通讯作者：
Wang Kun
中科院分区：
文献类型：
--
作者：
Tong Li;Yue Tao;Zuo Penglai;Zhang Xiaoxi;Wang Chenlong;Gao Jiajia;Wang Kun
制备了KI浸渍活性炭（KI-AC），考察了其在模拟烟气中对单质汞（Hg 0）的去除能力。KI负载量显著提高了Hg 0的去除性能。通过考察反应温度和活性炭孔隙率对除汞效果的影响，以及吸附态汞的脱附活化能的计算，确定了KI-AC的物化特性与除汞能力之间的关系。提高反应温度会削弱物理吸附在除汞过程中的作用。吸附态汞的BET比表面积和脱附活化能分析表明，Hg 0的去除是物理吸附和化学吸附的结合，化学吸附占主导地位.此外，还考察了烟气组分对KI-AC吸附除汞效果的影响，并提出了KI-AC吸附除汞的机理。I−离子在O2存在下的氧化是促进Hg 0去除的重要原因。SO 32-/SO 42-的生成促进了Hg 0的去除，而I2分子的竞争吸附和消耗则略微阻碍了Hg 0的去除。高浓度NO抑制HgO产物的生成。然而，KI-AC样品保持高活性对Hg 0去除在NO的存在下，因为与活性含N基团的反应。此外，Hg 0与KI-AC上产生的各种基团之间的亲和能力遵循以下顺序：N →含S基团。
The KI-impregnated activated carbon (KI-AC) was synthesized to investigate its capacity for elemental mercury (Hg0) removal under the simulated flue gas. The Hg0removal performance is significantly promoted by KI loading. The effect of reaction temperature and activated carbon porosity on Hg0removal, and calculation on desorption activation energy of adsorbed mercury species were employed to identify the relationships between the physicochemical characteristics of the KI-AC and Hg0removal capacity. Raising the reaction temperature weakens the function of physisorption in the process of Hg0removal. The Brunauer-Emmett-Teller (BET) surface area and desorption activation energy of the adsorbed mercury species analyses indicate that the Hg0removal occurs through a combination of physisorption and chemisorption, and the chemisorption dominates the reaction. In addition, the influences of flue gas components on Hg0removal over KI-AC were evaluated, and the adsorption mechanisms were proposed. Oxidation of I−ion by the presence of O2is the substantial reason that facilitates the Hg0removal. The Hg0removal performance is promoted by the generation of SO32−/SO42−and slightly frustrated by the competitive adsorption as well as consumption of I2molecules. Higher concentration of NO inhibits the generation of HgO products. However, the KI-AC sample remains highly active toward Hg0removal in the presence of NO because of the reaction with active N-containing groups. Additionally, the affinity capacities between Hg0and the various groups generated on the KI-AC follow the sequence: N → S-containing groups.