化学学报 ›› 2017, Vol. 75 ›› Issue (6): 594-601.DOI: 10.6023/A17030099 上一篇    下一篇

所属专题: 铁环境化学

研究论文

纳米零价铁对水中砷和硒去除的比较研究

夏雪芬, 滑熠龙, 黄潇月, 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:2017-03-13 出版日期:2017-06-15 发布日期:2017-05-24
  • 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.21677107,21307094,51578398)资助.

Removal of Arsenic and Selenium with Nanoscale Zero-Valent Iron (nZVI)

Xia Xuefen, Hua Yilong, Huang Xiaoyue, Ling Lan, Zhang Weixian   

  1. College of Environmental Science and Engineering, State Key Laboratory for Pollution Control and Resource Reuse, Tongji University, Shanghai 200092
  • Received:2017-03-13 Online:2017-06-15 Published:2017-05-24
  • Contact: 10.6023/A17030099 E-mail:linglan@tongji.edu.cn;zhangwx@tongji.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21677107, 21307094, 51578398).

采用纳米零价铁去除水中的砷和硒,考察了不同溶解氧、纳米零价铁投加量、接触时间以及溶液初始pH值等条件下纳米零价铁去除水中砷和硒的效果,并比较了反应前后固体的形貌、组成、溶液pH值及反应机制.结果表明,纳米零价铁可广泛用于去除水中的砷/硒污染,去除效果顺序依次为Se(IV)> As(Ⅲ)> Se(VI)> As(V);水中溶解氧(DO)对As(Ⅲ)和Se(IV)的去除没有显著的影响,而高浓度的DO对As(V)和Se(VI)的去除产生了一定的抑制作用;增加纳米零价铁投加量可促进砷和硒的去除;溶液初始pH值对纳米零价铁去除As(Ⅲ),As(V)和Se(VI)的影响较大,而对Se(IV)的去除几乎没有影响;反应后固体的形貌、组成及溶液pH值存在差异.纳米零价铁与砷、硒反应机理的不同造成了去除效果及反应后固液两相的差异.

关键词: 纳米零价铁, 砷, 硒, 去除

Arsenic (As(Ⅲ/V)) and selenium (Se(IV/VI)) are toxic inorganic contaminants in groundwater and industrial wastewater. The pollution caused by As and Se has become an environmental concern throughout the world. A variety of treatment technologies have been applied for As and Se removal from aqueous solutions. Among them, nanoscale zero-valent iron (nZVI) has been found to have a remarkable capability to remove As and Se from waters. Although lots of studies on the process of As and Se removal with nZVI are published, a systematic comparative study is still limited. In this study, the removal capacities of As(Ⅲ), As(V), Se(IV) and Se(VI) with nZVI in a single-specie system were compared. The performances of nZVI for As(Ⅲ), As(V), Se(IV) and Se(VI) were investigated on different conditions (including dissolved oxygen, nZVI dosage, contact time, and initial solution pH). The morphology and structure of fresh and spent nZVI were also examined by spherical aberration corrected scanning transmission electron microscopy (Cs-STEM) intergrated with energy-dispersive X-ray spectrometry (XEDS), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The batch experiments were conducted at room temperature in the 50-mL glass vials sealed with screwcaps. According to the speciation diagram, H3AsO30 and H2AsO4- are the respective predominant dissolved As(Ⅲ) and As(V) species respectively at pH 5.0; while HSeO3- and SeO42- are the predominant dissolved Se(IV) and Se(VI) species respectively at pH 5.0. The results showed that the removal capacities of As and Se investigated generally followed the order of Se(IV)> As(Ⅲ)> Se(VI)> As(V). Dissolved oxygen (DO) was found no apparent effects on the removal of As(Ⅲ) and Se(IV), while the removal performance of As(V) and Se(VI) was inhibited at high dissolved oxygen level (>14 mg/L). The removal of As and Se were enhanced with increasing nZVI dosage. Initial solution pH had no significant effect on Se(IV) removal, whereas the removal of As(Ⅲ), As(V), and Se(VI) appeared to be strongly dependent on the initial solution pH. The spent nZVI were different due to the different mechanisms of As(Ⅲ/V) and Se(IV/VI) reactions with nZVI. The results will be useful for the application of nZVI to the treatment of As/Se-containing wastewater.

Key words: nanoscale zero-valent iron (nZVI), arsenic, selenium, removal