| 刘丽,梁乐缤,时悦,王小治,封克,王圣森.硫掺杂零价铁去除Cr（Ⅵ）的机理及环境影响因素[J].农业环境科学学报,2021,40(5):1079-1087. |
| 硫掺杂零价铁去除Cr（Ⅵ）的机理及环境影响因素 |
| Sulfidation enhanced Cr(Ⅵ) reduction by zerovalent iron under different environmental conditions: A mechanistic study |
| 投稿时间：2020-10-25 |
| DOI：10.11654/jaes.2020-1225 |
| 中文关键词: 硫化零价铁 Cr（Ⅵ） 电化学 电子传递 |
| 英文关键词: sulfidated zerovalent iron Cr(Ⅵ) electrochemical electron transfer |
| 基金项目:国家自然科学基金面上项目（41977117，41771349）；2020年度扬州大学“青蓝工程”中青年学术带头人支持计划；2019年度扬州大学高端人才支持计划（拔尖人才成长计划）项目；扬州大学大学生科技创新基金项目（X20190527） |
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| 中文摘要: |
| 为提高对六价铬[Cr2O72-，Cr（Ⅵ）]的去除能力，采用硫代硫酸钠对零价铁（ZVI）进行改性。采用吸附实验研究所制备的硫化零价铁（S-ZVI）在不同环境条件下对溶液中Cr（Ⅵ）的去除能力，结合对材料的表征分析，探讨了S-ZVI去除Cr（Ⅵ）的机理。结果表明：硫掺杂后形成FeSx并覆盖在ZVI表层，所得S-ZVI的表面积约为ZVI的2倍。硫化改性有效地提高了材料对水体中Cr（Ⅵ）的吸附和还原能力。在pH为3时的吸附数据更符合准二级动力学模型和Langmuir吸附等温模型，其中S-ZVI对Cr（Ⅵ）的去除量约为ZVI的3倍。反应后材料的解吸实验和XPS分析显示Cr（Ⅵ）大部分被还原为Cr（Ⅲ），并进一步被吸附沉淀。硫化改性提高了ZVI的导电能力，从而提高了ZVI在Cr（Ⅵ）还原过程中的电子传递速率。低pH值和高温更有利于两种吸附剂对Cr（Ⅵ）的去除，而腐植酸（HA）抑制Cr（Ⅵ）的去除。因此，S-ZVI对Cr（Ⅵ）的去除包括还原、吸附和共沉淀机制，S-ZVI较好的性能可能与其良好的电化学特性和较大的表面积有关。 |
| 英文摘要: |
| Pristine zerovalent iron(ZVI) was sulfidated with sodium thiosulfate to improve its hexavalent chromium[Cr2O72-, Cr(Ⅵ)] removal capacity. The resulting sulfidated ZVI(S-ZVI) was tested for Cr(Ⅵ) sorption under different environmental conditions and then characterized using spectral techniques. The results showed that S-ZVI composites comprised the ZVI core surrounded by a FeSx shell, and the surface area was almost doubled relative to pristine ZVI. Sulfidation improved Cr(Ⅵ) sorption and reduction compared with ZVI, demonstrated in batch sorption experiments. The sorption data at a pH of 3 were better fitted with the second-order kinetics model and Langmuir isotherm model, revealing that Cr(Ⅵ) removal by S-ZVI was approximately three times that of ZVI. Desorption and XPS of exhausted sorbents clearly showed that Cr(Ⅵ) was dominantly reduced to Cr(Ⅲ), which was further adsorbed and precipitated on the sorbent surfaces. Sulfidation significantly increased the electrical conductivity of ZVI, thus improving its electron transfer rate during Cr(Ⅵ) reduction. Lower pH and elevated temperature were more favorable for Cr(Ⅵ) removal by both sorbents, whereas humic acid inhibited Cr(Ⅵ) removal. To conclude, Cr(Ⅵ) removal by S-ZVI invoke reduction, adsorption, and coprecipitation mechanisms, and the better performance of S-ZVI is likely ascribed to favorable electrochemical properties and a larger surface area. |
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