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首页> 外文期刊>Environmental Science & Technology >SCR Atmosphere Induced Reduction of Oxidized Mercury over CuO-CeO_2/TiO_2 Catalyst
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SCR Atmosphere Induced Reduction of Oxidized Mercury over CuO-CeO_2/TiO_2 Catalyst

机译：SCR气氛下CuO-CeO_2 / TiO_2催化剂上的氧化汞还原

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摘要

CuO-CeO_2/TiO_2 (CuCeTi) catalyst synthesized by a sol-gel method was employed to investigate mercury conversion under a selective catalytic reduction (SCR) atmosphere (NO, NH_3 plus O_2). Neither NO nor NH_3 individually exhibited an inhibitive effect on elemental mercury (Hg~0) conversion in the presence of O_2. However, Hg~0 conversion over the CuCeTi catalyst was greatly inhibited under SCR atmosphere. Systematic experiments were designed to investigate the inconsistency and explore the in-depth mechanisms. The results show that the copresence of NO and NH_3 induced reduction of oxidized mercury (Hg~(2+), HgO in this study), which offset the effect of catalytic Hg~0 oxidation, and hence resulted in deactivation of Hg~0 conversion. High NO and NH_3 concentrations with a NO/NH_3 ratio of 1.0 facilitated Hg~(2+) reduction and therefore lowered Hg~0 conversion. Hg~(2+) reduction over the CuCeTi catalyst was proposed to follow two possible mechanisms: (1) direct reaction, in which NO and NH_3 react directly with HgO to form N_2 and Hg~0; (2) indirect reaction, in which the SCR reaction consumed active surface oxygen on the CuCeTi catalyst, and reduced species on the CuCeTi catalyst surface such as Cu_2O and Ce_2O_3 robbed oxygen from adjacent HgO. Different from the conventionally considered mechanisms, that is, competitive adsorption responsible for deactivation of Hg~0 conversion, this study reveals that oxidized mercury can transform into Hg~0 under SCR atmosphere. Such knowledge is of fundamental importance in developing efficient and economical mercury control technologies for coal-fired power plants.
机译：采用溶胶-凝胶法合成的CuO-CeO_2 / TiO_2（CuCeTi）催化剂用于研究选择性催化还原（SCR）气氛（NO，NH_3加O_2）下的汞转化率。在O_2存在下，NO和NH_3均未对元素汞（Hg〜0）的转化产生抑制作用。然而，在SCR气氛下，CuCeTi催化剂上的Hg〜0转化受到很大抑制。设计了系统的实验，以调查不一致之处并探索深入的机制。结果表明，NO和NH_3的共存引起氧化汞的还原（本研究中Hg〜（2 +），HgO），抵消了Hg〜0的催化氧化作用，从而导致Hg〜0转化失活。 NO / NH_3比值为1.0的高NO和NH_3浓度促进了Hg〜（2+）的还原，因此降低了Hg〜0的转化率。提出在CuCeTi催化剂上还原Hg〜（2+）遵循两种可能的机理：（1）直接反应，其中NO和NH_3与HgO直接反应形成N_2和Hg〜0。 （2）间接反应，其中SCR反应消耗了CuCeTi催化剂上的活性表面氧，而还原后的CuCeTi催化剂表面上的物种如Cu_2O和Ce_2O_3则从相邻的HgO中夺走了氧气。与常规考虑的机制不同，竞争性吸附导致Hg〜0的转化失活，这项研究表明，氧化汞可以在SCR气氛下转化为Hg〜0。这些知识对于为燃煤电厂开发高效，经济的汞控制技术至关重要。

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  • 来源
    《Environmental Science & Technology》 |2015年第12期|7373-7379|共7页
  • 作者

    Hailong Li; Shaokang Wu; Chang-Yu Wu; Jun Wang; Liqing Li; Kaimin Shih;

  • 作者单位

    School of Energy Science and Engineering, Central South University, Changsha, China, 410083,Department of Civil Engineering, The University of Hong Kong, Hong Kong SAR, China;

    School of Energy Science and Engineering, Central South University, Changsha, China, 410083;

    Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment, University of Florida, Gainesville, Florida 32611, United States;

    Department of Occupational and Environmental Health, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73126, United States;

    School of Energy Science and Engineering, Central South University, Changsha, China, 410083;

    Department of Civil Engineering, The University of Hong Kong, Hong Kong SAR, China;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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