化学学报 ›› 2017, Vol. 75 ›› Issue (6): 529-537.DOI: 10.6023/A17020051 上一篇    下一篇

所属专题: 铁环境化学

研究评论

纳米零价铁与重金属的反应:“核-壳”结构在重金属去除中的作用

黄潇月, 王伟, 凌岚, 张伟贤   

  1. 同济大学 环境科学与工程学院 污染控制与资源化研究国家重点实验室 上海 200092
  • 收稿日期:2017-02-13 出版日期:2017-06-15 发布日期:2017-04-12
  • 通讯作者: 凌岚, 张伟贤 E-mail:linglan@tongji.edu.cn;zhangwx@tongji.edu.cn
  • 基金资助:

    项目受国家自然科学基金(Nos.21677107,51578398)资助.

Heavy Metal-nZVI Reactions: the Core-shell Structure and Applications for Heavy Metal Treatment

Huang Xiao-yue, Wang Wei, Ling Lan, Zhang Wei-xian   

  1. State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092
  • Received:2017-02-13 Online:2017-06-15 Published:2017-04-12
  • Contact: 10.6023/A17020051 E-mail:linglan@tongji.edu.cn;zhangwx@tongji.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21677107, 51578398).

重金属是一类毒性较高、处理难度较大的环境污染物.纳米零价铁因为具有高效分离、固定重金属的潜能而受到广泛关注.其独特的纳米级核壳结构和表面性质使纳米零价铁能够通过吸附、还原和沉淀等多种作用高效去除重金属.现代仪器分析手段的进步,特别是高分辨电子显微成像技术的发展,为深入研究纳米零价铁的微观结构以及纳米零价铁与重金属的作用机理开辟了新的视角.本文重点讨论了纳米零价铁的结构、性质及其在重金属去除中的作用.研究借助高分辨率的球差校正扫描透射电镜(Cs-STEM)成像,配合高灵敏度的X射线能谱仪(XEDS)进行化学分析,旨在更好地了解纳米零价铁的精细结构及其与重金属的界面反应过程和机理.在深入理论研究的同时,通过"小试-中试-工程"逐级放大的方法,系统论证了纳米零价铁处理重金属废水的可行性.结果表明,纳米零价铁可有效、同步去除实际废水中铜、砷、铅、锌等多种重金属,并具有较高的去除负荷.

关键词: 重金属, 纳米零价铁, 核-壳结构, 反应机理, 扫描透射电镜, 环境应用

Heavy metals are nonbiodegradable and bioaccumulative contaminants with high toxicity, thus heavy metal contamination and treatment have been hot research topics in recent years. Nanoscale zero-valent iron (nZVI) has received considerable attentions for its potential as a remedial agent for heavy metal sequestration and immobilization. In this paper, an overview is provided highlighting recent research progress on heavy metal-nZVI reactions, both laboratory studies and engineering applications are discussed. The core-shell structure with the core being metallic and the shell being iron oxides and the surface chemistry properties endow nZVI with unique and multifaceted functions for heavy metal removal including sorption, reduction and precipitation. Particle size of nZVI is in the range of nanoscale that imparts it with large specific surface area, high surface activity, and high density of reactive surface sites. A hybrid of effects, including instant separation, isolation, immobilization, and toxicity reduction can be achieved at the same time, making nZVI an effective remedial reagent for various heavy metals. Recent progress in instrumental analysis, especially the development of high-resolution electron microscopy, offers much-enhanced capability and new insights into the core-shell nature of nZVI and mechanisms of the heavy metal-nZVI reactions on a single nanoparticle. Research results obtained from a spherical aberration corrected scanning transmission electron microscopy (Cs-STEM) integrated with high sensitive X-ray energy dispersive spectroscopy (EDS) provide detailed information on the fine structural features of nZVI and the intraparticle reactions with individual nanoparticles. Technical feasibility and operational advantages of using nZVI for the treatment of industrial wastewater are assessed through systematic laboratory and pilot scale studies. Based on the encouraging results of bench-scale experiments, we have successfully applied nZVI for large scale applications of nZVI for treatment of industrial wastewater containing heavy metals such as Cu, As, Pb and Zn. The long-term operation results show tremendous potentials of nZVI-based process as an efficient method for heavy metal treatment.

Key words: heavy metal, nanoscale zero-valent iron (nZVI), core-shell structure, reaction mechanisms, STEM, environmental applications