| FeMnNi-LDHs对水中As(Ⅲ)的吸附性能与机制 |
| 摘要点击 3335 全文点击 1260 投稿时间：2020-05-03 修订日期：2020-06-30 |
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| 中文关键词 层状双氢氧化物(LDHs) 砷(As) 氧化 吸附去除 毒性控制 |
| 英文关键词 layered double hydroxides(LDHs) arsenic (As) oxidation adsorption removal toxicity control |
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| 中文摘要 |
| 稳定和高效地去除地下水中的As（Ⅲ）仍然是一个具有挑战的全球性问题.本研究以Fe、Mn和Ni这3种元素作为层板阳离子，采用共沉淀法制备出三金属层状双氢氧化物FeMnNi-LDHs，利用XRD、TEM、FT-IR和XPS等技术对其结构进行表征，并探讨其对水中As（Ⅲ）的吸附去除能力与机制.结果表明，FeMnNi-LDHs具有层状双氢氧化物的典型特征峰，峰型尖锐，结晶度高，TEM图像也显示有明显的层状结构.其对As（Ⅲ）的吸附动力学符合准二级动力学模型，等温吸附曲线符合Freundlich等温方程，45℃时最大吸附量为240.86 mg·g-1，明显高于其他层状双氢氧化物.在pH为2~9范围内，FeMnNi-LDHs对As（Ⅲ）均有较好的吸附效果.水中共存PO43-和CO32-离子对As（Ⅲ）存在竞争吸附，而NO3-、Cd2+和Pb2+影响较小.其去除吸附机制主要为氧化、离子交换和配位络合，其中Mn在As（Ⅲ）的氧化过程中有重要贡献.制备出的FeMnNi-LDHs对水中As（Ⅲ）的吸附去除和毒性控制具有良好的应用潜力. |
| 英文摘要 |
| Removing As(Ⅲ)from water steadily and efficiently is still a challenging global issue. In this study, novel FeMnNi-LDHs were prepared by a co-precipitation method using Fe, Mn, and Ni as lamellar cations, and the structure were characterized by XRD, TEM, FT-IR, and XPS techniques, and the adsorption performance and mechanism of As(Ⅲ)was explored. The results showed that FeMnNi-LDHs have typical characteristic peaks of layered double hydroxides, with sharp peaks and high crystallinity. The TEM images also show obvious layered structures. The adsorption kinetics of As(Ⅲ)on FeMnNi-LDHs agree with the quasi second-order kinetic model, and the isotherm adsorption curve agrees with the Freundlich isotherm equation. The maximum adsorption capacity at 45℃ was 240.86 mg·g-1, which is significantly higher than other similar layered double hydroxides. Acidity had little effect on the adsorption performance of As(Ⅲ), and it had a good adsorption effect in the range of pH 2-9. The coexistence of PO43- and CO32- ions in water showed adverse effects on the As(Ⅲ) adsorption capacity, and NO3-, Cd2+, and Pb2+ had less influence. The adsorption mechanism of FeMnNi-LDHs for As(Ⅲ) includes ion exchange, oxidation, and coordination complexation, in which Mn plays a major role in the oxidation process of As(Ⅲ). The prepared FeMnNi-LDHs exhibited good application potential in the adsorption of As(Ⅲ) from water and toxicity control. |
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