JOURNAL OF HAZARDOUS MATERIALS
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2020
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IF 9.038
Li Liang,Xiaoqin Li,Yiqing Guo,Zhang Lin,Xintai Su,Bo Liu
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 (Fe 3 O 4 ), 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 0 and SO 4 2- . The removal mechanisms are strongly dependent on the solubility product constant (K sp ) of metal sulfides. For Hg(II) and Ag(I), with K sp 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 sp 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 sp of corresponding metal sulfides slightly lower than that of iron sulfide, are mainly removed by complexation with surface groups of S-nZVI.
研究领域:
环境科学
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化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
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2023
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IF 7.7
Yuwei Ding,Meng Li,Qian Zhang,Yibo Zhang,Zhixuan Xia,Xiangyu Liu,Nanping Wu,Jie Peng
To improve the performance of the nanoscale zero-valent iron (nZVI)-based advanced oxidation process (AOPs), a sulfidation pre-modification endowed nZVI with stable reduction nature mechanism was proposed, and a coupled system of activating PMS with sulfidized nanoscale zero-valent iron supported by biochar(S-nZVI/BC@PMS) was constructed in this study. It could be found that sulfidation state and formation, largely dependent on the sulfidized modification method, had a great impact on the enhancement for nZVI/BC in activating PMS for Acid Red 73 degradation. Compared with original nZVI/BC, the formed FeS shell blocked the external air to protect the internal Fe 0 , and S-nZVI/BC became relatively hydrophobic, which could slow down the material corrosion by water and dissolved oxygen to enhance the reaction durability. Appropriate sulfidation reduced the electrochemical impedance and enhanced the electrical conductivity of the catalyst, which facilitated the electron transfer in the system, and the participation of reducing sulfur species enabled the reaction to form a positive cycle and ensure a prolonged duration. Excessive sulfidation caused the material to become unstable and thus susceptible to air erosion, reducing the efficiency of contaminant removal. Due to the FeS protective shell, hydrophobicity of S-nZVI/BC and the promoted electron transfer in the system, S-nZVI/BC@PMS system secured more free radicals and had longer reaction time under the same conditions. In addition, S-nZVI/BC had good antioxidant properties, universality, and reusability for practical applications. These findings not only elucidated the superiority of S-nZVI/BC@PMS system but also provided new insights into cost-saving and efficient advanced oxidation processes.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Weiying Li,Li Liang,Yue Li,Yu Tian,Jiping Chen,Sheng Chen,Junpeng Zhang
Recently, EDTA-chelated Cd II (Cd II -EDTA) was effectively removed by sulfidated nanoscale zero-valent iron (S-nZVI). However, few studies have been performed to investigate the influence of co-existing ions and emerging contaminants (such as microplastics) on the performance of S-nZVI toward Cd II -EDTA, which is vital for the application of S-nZVI in practical wastewater treatment. In this study, the individual effects of different co-existing ions (NO 3 − , SO 4 2− , PO 4 3− , Mg 2+ , Cu 2+ , and Zn 2+ ) and polystyrene (PS) microplastics with different concentrations on the removal of Cd II -EDTA by S-nZVI were systematically investigated. The removal capacity of S-nZVI toward Cd II -EDTA fell in the range of 579.3–644.7, 612.3–670.2, 607.4–691.3, 533.3–623.6, 79.9–545.3, 544.3–631.7, and 568.6–663.8 mg/g for the presence of NO 3 − , SO 4 2− , PO 4 3− , Mg 2+ , Cu 2+ , Zn 2+ , and PS microplastics over the concentration range of 10.0–150.0 mg/L, respectively, which were all smaller than that of the system of Cd II -EDTA alone (746.6 mg/g), indicating that all of the investigated co-existing substances showed inhibitory effects on Cd II -EDTA removal. As for NO 3 − , SO 4 2− , or Mg 2+ -containing system, the inhibitory effect was ascribed to the influence of S-nZVI corrosion rate; As for PO 4 3− , Mg 2+ , Cu 2+ , Zn 2+ , or PS microplastics-containing system, the negative effect was caused by changing the corrosion of S-nZVI and occupying the reactive sites at the surface of S-nZVI. The final corrosion products of S-nZVI under different reaction conditions were strongly dependent on the species and concentration of co-existing substance with the combinations of γ-FeOOH, α-Fe 2 O 3 , FeO, or β-FeOOH as the dominant corrosion products.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）