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.
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。
