物理化学学报 >> 2015, Vol. 31 >> Issue (3): 512-518.doi: 10.3866/PKU.WHXB201412251

催化和表面科学 上一篇    下一篇

硝酸改性活性炭上氧/氮官能团对脱汞性能的促进作用

佟莉1,2, 徐文青1, 亓昊1,2, 周璇1, 刘瑞辉1, 朱廷钰1   

  1. 1. 中国科学院过程工程研究所, 湿法冶金清洁生产技术国家工程实验室, 北京市过程污染控制技术研究中心, 北京 100190;
    2. 中国科学院大学, 北京 100049
  • 收稿日期:2014-10-13 修回日期:2014-12-25 发布日期:2015-03-06
  • 通讯作者: 朱廷钰 E-mail:tyzhu@ipe.ac.cn
  • 基金资助:

    国家重点基础研究发展规划项目(973) (2013CB430005)和国家高技术研究发展计划项目(863) (2013AA065501, 2013AA065404)资助

Enhanced Effect of O/N Groups on the Hg0 Removal Efficiency over the HNO3-Modified Activated Carbon

TONG Li1,2, XU Wen-Qing1, QI Hao1,2, ZHOU Xuan1, LIU Rui-Hui1, ZHU Ting-Yu1   

  1. 1. Beijing Engineering Research Center of Process Pollution Control, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China;
    2. University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2014-10-13 Revised:2014-12-25 Published:2015-03-06
  • Contact: ZHU Ting-Yu E-mail:tyzhu@ipe.ac.cn
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2013CB430005) and National Hi-Tech Research and Development Program of China (863) (2013AA065501, 2013AA065404).

摘要:

采用硝酸氧化手段对活性炭进行了表面处理, 并在固定床反应器上测试了其脱除单质汞的性能. 研究表明, 在模拟烟气中硝酸改性活性炭能有效脱除单质汞. 采用元素分析、Brunauer-Emmett-Teller (BET)比表面积、扫描电子显微镜(SEM)、拉曼(Raman)光谱、Boehm滴定、程序升温脱附(TPD)和X射线光电子能谱(XPS)等手段研究了活性炭表面官能团对其脱汞性能的影响. 结果表明: 硝酸氧化处理能同时增加活性炭表面含氧官能团和含氮官能团的含量. 与改性活性炭的物理性质相比, 其化学性质对脱汞性能的影响更大, 单质汞主要被改性活性炭氧化为HgO而去除. 在脱汞反应中, 羰基、酯基和酸酐等含氧官能团可能是活性吸附位点, 反应后这些官能团被还原为羟基或者醚基; 而吡咯等含氮官能团可能是活性催化位点. 此外, 基于上述表征结果提出了硝酸改性活性炭表面官能团的脱汞机制.

关键词: 单质汞, 活性炭, 硝酸, 氧官能团, 氮官能团

Abstract:

HNO3-modified activated carbon (AC) was prepared to determine its mercury removal ability on a fixed-bed reactor. In this study, the HNO3-modified AC was found to be effective for mercury removal in simulated flue gas. The original sample, the HNO3-modified sample and the production sample were characterized by elemental analysis, Brunauer-Emmett-Teller (BET) specific surface area measurements, scanning electron microscopy (SEM), Raman spectra, Boehm titrations, temperature programmed desorption (TPD) technique, and X-ray photoelectron spectroscopy (XPS). The results show that HNO3 treatment increases the content of oxygen and nitrogen on the AC. Compared with the physical characteristics of HNO3-modified AC, the effects of its chemical characteristics on mercury removal are more significant. The Hg0 is mainly oxidized to HgO by the HNO3-modified AC. The oxygen functional groups, possibly carbonyls, esters or anhydrides were found to be the adsorption sites for mercury removal, and these groups were reduced to hydroxyl groups or ether groups. The N-functional groups, possibly pyrrolic tautomers, were found to be the active catalytic sites. The mechanism for Hg0 removal by HNO3-modified activated carbon is proposed based on the characterization results.

Key words: Elemental mercury, Activated carbon, HNO3, Oxygen functional group, Nitrogen functional group

MSC2000: 

  • O647