高等学校化学学报 ›› 2023, Vol. 44 ›› Issue (2): 20220470.doi: 10.7503/cjcu20220470

• 物理化学 • 上一篇    下一篇

制备高活性纳米零价铁的甘露醇改性机理

贺玉婷1, 牛慧斌2, 张兆年4, 张静1, 付桂荣2, 陈春城3, 黄应平2, 方艳芬1,2()   

  1. 1.三峡大学材料与化工学院, 宜昌 443002
    2.三峡库区生态环境教育部工程研究中心, 宜昌 443002
    3.中国科学院化学研究所, 北京 100190
    4.湖北省生态环境厅宜昌生态环境监测中心, 宜昌 443005
  • 收稿日期:2022-07-11 出版日期:2023-02-10 发布日期:2022-09-19
  • 通讯作者: 方艳芬 E-mail:chem_ctgu@126.com
  • 基金资助:
    国家自然科学基金(22136003);111引智项目(D20015);三峡库区生态环境教育部工程研究中心开放基金(KF2022-03)

Modification Mechanism of Mannitol for Preparation of Highly Active Nano-zerovalent Iron

HE Yuting1, NIU Huibin2, ZHANG Zhaonian4, ZHANG Jing1, FU Guirong2, CHEN Chuncheng3, HUANG Yingping2, FANG Yanfen1,2()   

  1. 1.College of Materials and Chemical Engineering,China Three Gorges University,Yichang 443002,China
    2.Engineering Research Center of Eco?environment in Three Gorges Reservoir Region,Ministry of Education,China Three Gorges University,Yichang 443002,China
    3.Institute of Chemistry Chinese Academy of Sciences,Beijing 100190,China
    4.Hubei Provincial Department of Ecology and Environment Yichang Ecological Environment Monitoring Center,Yichang 443005,China
  • Received:2022-07-11 Online:2023-02-10 Published:2022-09-19
  • Contact: FANG Yanfen E-mail:chem_ctgu@126.com
  • Supported by:
    the National Natural Science Foundation of China(22136003);the Program of Introducing Talents of Discipline to Universities, China(D20015);the Three Gorges Reservoir Area Ecological Environment Education Ministry Engineering Research Center Open Fund, China(KF2022-03)

摘要:

纳米零价铁(Nano zero-valent iron, nZVI)被广泛应用于水污染治理, 高纯度且分散性良好的nZVI的制备方法一直是研究热点. 本文采用含不同羟基数目的醇(乙醇、 乙二醇、 赤藓糖醇、 甘露醇和山梨醇)作为改性剂, 分别制备得到nZVI-EA, nZVI-EG, nZVI-ER, nZVI-M和nZVI-S样品. 将上述样品应用于水中微囊藻毒素(Microcystin-LR, MC-LR)的还原去除. 结果表明, 随着改性剂羟基数目的增多, 改性nZVI的抗氧化能力和分散性增强, 对MC-LR的降解反应速率也随之提高. nZVI-M去除MC-LR的表面积校正特征速率常数(79.35×10-5 L·m‒2·min‒1)是nZVI-S(8.55×10-5 L·m‒2·min‒1)的9.3倍, 是未改性样品nZVI0(1.30×10-5 L·m‒2·min‒1)的61.0倍. 通过X射线衍射(XRD)、 能谱分析(EDS)和重铬酸钾滴定法等表征发现, 这可能是由于nZVI-M的Fe0纯度最高(总铁含量为83.5%). 用光学显微镜观察nZVI-M的制备过程发现, Fe0表面有透明棒状的甘露醇晶体簇形成, 提高了nZVI的抗氧化能力和在水中的分散性, 实现了对MC-LR的高效降解. 与山梨醇的羟基呈“两极”分布不同, 甘露醇羟基呈“锯齿状”分布, 且其O2p 轨道易发生电子离域, 能与Fe3+形成强配位.

关键词: 纳米零价铁, 甘露醇, 山梨醇, 改性, 去除

Abstract:

Nano zero-valent Iron(nZVI) has been widely used in water pollution treatment. The preparation method of nZVI with high purity and good dispersion has always been a research focus. In this paper, alcohols with different numbers of hydroxyl groups were used as modifiers, including ethanol, ethylene glycol, erythritol, mannitol and sorbitol, to prepare nZVI-EA, nZVI-EG, nZVI-ER, nZVI-M and nZVI-S sample, respectively. The above samples were applied to the reduction and removal of microcystin(Microcystin-LR, MC-LR) in water. The results showed that with the increase of hydroxyl groups, the antioxidant capacity and dispersity of modified nZVI were enhanced, and the degradation rate of MC-LR was also increased. The surface-area-normalized rate coefficient of nZVI-M(79.35×10-5 L·m‒2·min‒1) was 9.3 times that of nZVI-S(8.55×10-5 L·m‒2·min‒1) and 61.0 times that of nZVI0(unmodified sample, 1.30×10-5 L·m‒2·min‒1). It was found by X-ray diffraction(XRD), energy dispersive spectroscopy(EDS) and potassium dichromate titration that this may be due to the highest Fe0 purity of nZVI-M(total iron content is 83.5%). In order to reveal the modification mechanism, the preparation process of nZVI-M was observed by optical microscope. It was found that transparent rod-like mannitol crystal clusters formed on the surface of Fe0, which improved the antioxidant capacity and dispersion of nZVI in water, and realized the efficient degradation of MC-LR. Unlike the hydroxyl group of sorbitol, the hydroxyl group of mannitol has a “jagged” distribution and its O2p orbital is prone to electron delocalization to form strong coordination with Fe3+. This will provide a new way to obtain nZVI with high purity and good dispersion by the coordination of alcohol hydroxyl groups.

Key words: Nano zero-valent iron, Mannitol, Sorbitol, Modification, Removal

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