硫化纳米零价铁（S-nZVI）去除重金属阳离子：反应机制与硫的作用。
The removal of heavy metal cations by sulfidated nanoscale zero-valent iron (S-nZVI): The reaction mechanisms and the role of sulfur.
机构信息
School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou 510006, PR China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of the Ministry of Education, South China University of Technology, Guangzhou 510006, PR China.
出版信息
J Hazard Mater. 2021 Feb 15;404(Pt A):124057. doi: 10.1016/j.jhazmat.2020.124057. Epub 2020 Sep 25.
In this study, the reaction between sulfidated nanoscale zero-valent iron (S-nZVI) and heavy metal cations as well as the role of sulfur were investigated. The results showed the corrosion products of S-nZVI were lepidocrocite (γ-FeOOH) or/and magnetite (FeO), depending on heavy metal species. While the removal of Hg(II), Ag(I), Cu(II), and Pb(II) by S-nZVI was rapid and could achieve over 99% within 5 mins, the removal of Ni(II) and Zn(II) was low in efficiency and unstable. Sulfur was existed as iron sulfides at fresh S-nZVI, but was displaced by the heavy metals and formed the related sulfide compound, or oxidized to S and SO. The removal mechanisms are strongly dependent on the solubility product constant (K) of metal sulfides. For Hg(II) and Ag(I), with K of corresponding metal sulfides much lower than that of iron sulfide, the removal mechanism is the displacement reaction. For Cu(II) and Pb(II), with K of corresponding metal sulfides moderately lower than that of iron sulfide, the removal mechanisms are the displacement reaction and complexation with surface groups of S-nZVI. For Zn(II) and Ni(II), whose K of corresponding metal sulfides slightly lower than that of iron sulfide, are mainly removed by complexation with surface groups of S-nZVI.
在这项研究中，研究了硫化纳米零价铁（S-nZVI）与重金属阳离子的反应以及硫的作用。结果表明，S-nZVI 的腐蚀产物取决于重金属种类，可以是纤铁矿（γ-FeOOH）或/和磁铁矿（FeO）。虽然 S-nZVI 对 Hg(II)、Ag(I)、Cu(II)和 Pb(II)的去除迅速，在 5 分钟内可达到 99%以上，但对 Ni(II)和 Zn(II)的去除效率低且不稳定。硫在新鲜的 S-nZVI 中以铁硫化物的形式存在，但被重金属取代并形成相关的硫化物化合物，或被氧化为 S 和 SO。去除机制强烈依赖于金属硫化物的溶度积常数 (K)。对于 Hg(II)和 Ag(I)，其相应金属硫化物的 K 远低于铁硫化物的 K，去除机制是置换反应。对于 Cu(II)和 Pb(II)，其相应金属硫化物的 K 略低于铁硫化物的 K，去除机制是置换反应和与 S-nZVI 表面基团的络合。对于 Zn(II)和 Ni(II)，其相应金属硫化物的 K 略低于铁硫化物的 K，主要通过与 S-nZVI 表面基团的络合去除。
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