铝掺杂针铁矿的制备、表征及吸附氟的特性

发布时间：2018-06-05 03:06

本文选题：针铁矿 + 铝掺杂针铁矿　；参考：《无机化学学报》2017年12期

【摘要】：水热条件下制备了针铁矿(Goe)和几种铝掺杂针铁矿(Goe-Al_(0.1),Goe-Al_(0.2)和Goe-Al_(0.4)),用X射线衍射(XRD)、扫描电镜(SEM)、氮气物理性吸附、酸碱滴定等手段对样品进行了表征,并研究了它们对氟离子的吸附特性。结果表明,随着铝掺杂量的增加,铝掺杂针铁矿的结晶度不断减弱、颗粒的长度不断减小。4种样品的微孔表面积、孔体积和表面分形度都表现为GoeGoeAl0.1Goe-Al_(0.2)Goe-Al_(0.4),而孔径分布表现为相反的顺序。Goe、Goe-Al_(0.1)、Goe-Al_(0.2)和Goe-Al_(0.4)的电荷零点(PZC)分别为8.2、8.3、8.5和8.7,pH=5.0时它们的表面电荷量分别为0.66、0.83、1.03和1.19 mmol·g~(-1)。准二级动力学模型适合描述4种样品对氟的吸附动力学过程,表明化学吸附是主要作用机制。一位Langmuir模型可较好的拟合等温吸附数据(R2为0.967~0.981),二位Langmuir模型对等温吸附数据的拟合度更高(R2为0.982~0.995),而Freundlich模型的拟合度较低(R2为0.877~0.912)。初始pH=5.0时,Goe、Goe-Al_(0.1)、Goe-Al_(0.2)和Goe-Al_(0.4)对氟的最大吸附容量分别为8.83、10.24、11.72和12.86 mg·g~(-1)。可见,铝掺杂针铁矿对土-水环境中氟的吸附容量高于纯针铁矿。
[Abstract]:Goethite (Goe) and several aluminum-doped goethite (Goe-Almex) and Goe-AlD (0.2) and Goe-AlDX were prepared under hydrothermal conditions. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), nitrogen physical adsorption, acid-base titration and so on, and their adsorption properties for fluorine ions were studied. The results show that the crystallinity of aluminum-doped goethite decreases with the increase of Al doping content, and the particle length decreases the micropore surface area of 4 kinds of samples. Both the pore volume and the surface fractal degree are shown as GoeGoeAl0.1Goe-Altip 0.2Goe-Altip, while the pore size distribution shows the opposite order. GoeGoe-Altix 0.2and Goe-Al201 (0.4) the charge zero point PZC) of GoeGoeAl0.1Goe-AlAlC (8.28.3hg) and 8.7hu (pH5.0) are 0.660.83h1.03 and 1.19 mmol / g ~ (-1), respectively. The quasi-second-order kinetic model is suitable for describing the adsorption kinetics of fluorine on four samples, which indicates that chemisorption is the main mechanism. One Langmuir model can better fit the isothermal adsorption data (R ~ 2 = 0.967N 0.981g), and the two-position Langmuir model has a higher fitting degree (R ~ 2 = 0.982) than that of the Freundlich model (r ~ 2 = 0.877 ~ 0.912). The maximum adsorption capacities for fluorine in Goe-Altix (0.2and Goe-Al0.40) are 8.83 ~ 10.24 ~ 11.72 and 12.86 mg / g ~ (-1), respectively. It can be seen that the adsorption capacity of aluminum doped goethite to fluorine in soil-water environment is higher than that of pure goethite.
【作者单位】：四川文理学院化学化工学院;湖北民族学院化学与环境工程学院;
【基金】：国家自然科学基金(No.41561053,41261060) 四川省教育厅科研项目(No.15ZA0317) 达州市科技局应用基础研究项目(No.KJJ201403)资助
【分类号】：O614.811

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