| 氧化铁改性蛭石的制备、表征及吸附氟的特性 |
| Preparation, Characterization and Fluoride Adsorption Characteristics of Iron-Oxide-Modified Vermiculite |
| 作者 | 单位 | E-mail | | 魏世勇 | 湖北民族学院化学与环境工程学院, 生物资源保护与利用湖北省重点实验室, 恩施 445000 | xiangju12345@126.com | | 王锐 | 湖北民族学院化学与环境工程学院, 生物资源保护与利用湖北省重点实验室, 恩施 445000 | | | 牛鹏举 | 湖北民族学院化学与环境工程学院, 生物资源保护与利用湖北省重点实验室, 恩施 445000 | | | 方敦 | 湖北民族学院化学与环境工程学院, 生物资源保护与利用湖北省重点实验室, 恩施 445000 | | | 杨小洪 | 湖北民族学院化学与环境工程学院, 生物资源保护与利用湖北省重点实验室, 恩施 445000 | | | 但悠梦 | 湖北民族学院化学与环境工程学院, 生物资源保护与利用湖北省重点实验室, 恩施 445000 | |
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| 摘要: 采用共沉淀法制备了3种不同含铁量的氧化铁改性蛭石（Verm-Fex，x=5，10，20），研究了纯蛭石（Verm）和Verm-Fex的表面性质及吸附氟的特性。与样品Verm比较，3种Verm-Fex中Verm的d（002）层间距略有升高；Verm-Fex的孔体积、表面积、表面分形度均随含铁量的增加而升高，其中微孔体积和外表面积的增加幅度更明显。4种样品的等电点（IEP）也随含铁量的增加而明显升高；初始pH＝5.0时，它们的表面ζ电位分别为-16.4，-6.1，10.5和28.4 mV。4种样品对氟的等温吸附数据用单吸附位Langmuir模型拟合（R2=0.973~0.995）时，Verm的R2最高；双吸附位Langmuir模型可很好地描述3种Verm-Fex样品的等温吸附过程（R2=0.991~0.998）；Freundlich模型对4种样品吸附数据的拟合度较差（R2=0.835~0.937），但R2随样品含铁量的增加而略微升高。初始pH=5.0时，Verm和Verm-Fex（x=5，10，20）对氟的最大吸附容量（qmax）分别为3.18，6.76，9.27和12.43 mg·g-1。可见，Verm-Fex（尤其含铁量较高的产物）对表生环境中氟的吸附固定性能明显高于Verm。 |
| 关键词: 蛭石 氧化铁改性蛭石 表面性质 吸附 氟 |
| 基金项目: 国家自然科学基金（No.41261060，41561053）和生物资源保护与利用湖北省重点实验室开放基金（No.PKLHB1315）资助项目。 |
| Abstract: Iron-oxide-modified vermiculite (Verm-Fex, x=5, 10, 20) was prepared by a co-precipitation procedure. The surface properties and fluoride adsorption of pure vermiculite (Verm) and Verm-Fex were investigated. Compared to Verm, the d(002) spacing of Verm in Verm-Fex increases slightly, and the pore volumes, different surface areas and surface fractal dimension of Verm-Fex increase with increasing the Fe contents. The increased magnitude of the micropore volume and external surface area of Verm-Fex is more significant. The isoelectric point (IEP) of the samples increases in the order of Verm < Verm-Fe5 < Verm-Fe10 < Verm-Fe20, and the ζ potential at pH 5.0 of the four samples is -16.4, -6.1, 10.5, and 28.4 mV, respectively. One-site Langmuir model was used to describe the fluoride adsorption by the samples (R2=0.973~0.995), and the determination coefficient (R2) for Verm is the highest. The R2 fitted from two-site model for Verm-Fex (x=5, 10, 20) is higher than that from one-site model, indicating that the adsorption data of Verm-Fex can be fitted by two-site model well. The R2 fitted from Freundlich model of the samples is lying in the range of 0.835~0.937 and follows the sequence of Verm < Verm-Fe5 < Verm-Fe10 < Verm-Fe20. This indicates that Verm-Fex possesses the heterogeneous surfaces with different reactive sites. When pH=5.0, the adsorption capacities (qmax) of Verm, Verm-Fe5, Verm-Fe10 and Verm-Fe20 are 3.18, 6.76, 9.27 and 12.43 mg·g-1, respectively. Compared to Verm, Verm-Fex with a high Fe content has a higher adsorption capacity for fluoride in solutions. |
| Keywords: vermiculite iron-oxide-modified vermiculite surface properties adsorption fluoride |
| 投稿时间：2016-04-20 修订日期：2016-07-08 |
| 摘要点击次数: 1680 |
| 全文下载次数: 1537 |
| 魏世勇,王锐,牛鹏举,方敦,杨小洪,但悠梦.氧化铁改性蛭石的制备、表征及吸附氟的特性[J].无机化学学报,2016,32(9):1619-1628. |
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