钨钼酸盐纳米材料的制备及其性质研究

发布时间：2018-03-23 20:44

本文选题：液相合成　切入点：钼酸盐　出处：《安徽大学》2015年硕士论文

【摘要】：当今世界环境问题日益突出,含重金属离子和有机污染物的废水大量排放,不仅给生态环境同时也给人类健康带来严重危害。因此,如何有效去除这些污染物成为众多科技工作者致力解决的难点热点。纳米材料以其独特、优良的性质在水处理领域显示了无可比拟的优越性,可实现对水体中污染物的快速吸附或降解。本文采用简单的液相合成法成功地制备出了一系列性质优良的钨钼酸盐微/纳米材料,不仅研究了相关实验条件对样品结构、形貌的影响,还根据实验现象提出可能的形成机理,最后进一步研究了合成材料在水处理方面的应用。主要内容如下：1.采用改进的缓释共沉淀法成功合成了红细胞状钼酸钙(CaMoO4),用X射线衍射仪(XRD)、傅立叶红外光谱仪(FT-IR)、拉曼光谱仪(Raman)以及扫描电子显微镜(SEM)对其结构和形貌进行了表征。研究发现MoO42-缓慢释放利于形成形貌均匀的红细胞状CaMo04,而直接结合易形成尺寸分布较宽的桃核状CaMoO4;酸性条件抑制Mo7O246-的水解,形成红细胞状结构；碱性条件促进Mo7O246-的水解,作用方式与直接结合类似。此外,红细胞状CaMoO4在536nm呈现一个强而宽的荧光发射峰。最后,红细胞状CaMoO4对亚甲基蓝显示了较高的去除效率和良好的稳定性,展现了在水处理方面潜在的应用前景。2.使用阴离子表面活性剂十二烷基硫酸钠(SDS)-尿素(Urea)辅助水热法成功合成了3D花状钨酸锌(ZnWO4),采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)对其结构和形貌进行了表征。研究发现：SDS-Urea的协同作用促使ZnWO4由零维、一维向三维结构转变,在诱导3D花状ZnWO4形成中起到重要作用。以3D花状ZnWO4作为吸附剂,铜离子溶液为模拟废水,测定其在水体中的吸附行为,结果显示3D花状ZnWO4对Cu2+吸附性能优于商品活性炭,最大吸附容量达293.1 mg·g-1。良好吸附性能归因于3D花状ZnWO4较大的比表面积、丰富的孔隙结构和表面负电性的协同作用。铜离子在3D花状ZnWO4上的吸附动力学模型与拟二级动力学方程相符,吸附等温线符合Freundlich吸附模型。3.采用水热法在相对较低温度成功合成了板栗状介孔钨酸镍(NiWO4),用X射线衍射仪(XRD)、傅立叶红外光谱仪(FT-IR)、扫描电子显微镜(SEM)对其结构和形貌进行了表征。研究发现,NiWO4的形貌在很大程度上与水热反应温度有关,可用奥斯特瓦尔德熟化机理解释其形成过程。相比于商品活性炭,NiWO4纳米微球由于其独特的介孔结构和较大的比表面积,表现出对阳离子染料更高的吸附性能。更重要的是,介孔NiWO4在使用三次以后依然保持了较高的稳定性,有望成为一种优良的吸附剂。MB在介孔NiWO4上的吸附动力学模型与拟二级动力学方程相符,吸附等温线符合Freundlich吸附模型。
[Abstract]:Nowadays, the environmental problems in the world are becoming more and more prominent. The waste water containing heavy metal ions and organic pollutants is discharged in large quantities, which not only brings serious harm to the ecological environment but also to human health. How to effectively remove these pollutants has become a difficult point for many scientific and technological workers to solve. Nanomaterials have shown unparalleled advantages in the field of water treatment with their unique and excellent properties. In this paper, a series of tungsten molybdate micro / nano materials with excellent properties have been successfully prepared by simple liquid phase synthesis method. According to the experimental phenomena, the possible formation mechanism is also proposed. Finally, the application of synthetic materials in water treatment is further studied. The main contents are as follows: 1. The red blood cell calcium molybdate calcium molybdate (CaMoO _ 4) has been successfully synthesized by an improved slow-release co-precipitation method. The X-ray diffractometer (XRDX), Fourier transform infrared spectrometer (FTIR) and FT-IRN have been used to synthesize red blood cell calcium molybdate (CaMoO _ 4). Its structure and morphology were characterized by Raman Spectrometer (Raman) and scanning Electron Microscopy (SEM). It was found that slow release of MoO42- was beneficial to the formation of uniform RBC CaMo04, while it was easy to form peach kernelike with wide size distribution. The acidic condition inhibited the hydrolysis of Mo7O246-. In addition, erythrocyte like structure was formed, alkaline condition promoted the hydrolysis of Mo7O246- in the same way as direct binding. In addition, erythrocyte like CaMoO4 showed a strong and wide fluorescence emission peak in 536nm. Erythrocyte CaMoO4 showed high removal efficiency and good stability to methylene blue. The potential application prospect in water treatment is shown. 2. 3D zinc tungstate znwo _ 4 has been successfully synthesized by using anionic surfactant sodium dodecyl sulfate (SDS- Urea) assisted hydrothermal method. X-ray diffractometer (XRD) and scanning electron microscopy (SEM) have been applied to the synthesis of ZnWO _ 4H _ 4H _ 2O _ 4H _ 2O _ 4. The structure and morphology of ZnWO4 were characterized by SEM. It was found that the synergistic action of the ZnWO4 at 1: SDS-Urea promoted the change of ZnWO4 from zero dimension to zero dimension. The transition from one dimension to three dimensional structure plays an important role in inducing the formation of 3D flower-like ZnWO4. The adsorption behavior of 3D flower-like ZnWO4 in water was measured with copper ion solution as the simulated wastewater. The results showed that the adsorption of Cu2 by 3D flower-shaped ZnWO4 was superior to that of commercial activated carbon, and the maximum adsorption capacity was 293.1 mg g ~ (-1). The good adsorption capacity was attributed to the large specific surface area of 3D flower-shaped ZnWO4. The adsorption kinetics model of copper ions on 3D flower-like ZnWO4 agrees with the pseudo-second-order kinetic equation. The adsorption isotherm accords with the Freundlich adsorption model .3.The structure and shape of the mesoporous nickel tungstate (Niwo _ 4) have been successfully synthesized by hydrothermal method at relatively low temperature. Its structure and shape were characterized by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). It was found that the morphology of NiWO4 was related to the hydrothermal reaction temperature to a great extent. The formation process can be explained by the maturation mechanism of Osterwald. Compared with commercial activated carbon, NiWO4 nanospheres exhibit higher adsorption properties to cationic dyes due to their unique mesoporous structure and larger specific surface area. After using mesoporous NiWO4 for three times, the adsorption kinetics model of mesoporous NiWO4 on mesoporous NiWO4 is expected to be a good adsorbent. The adsorption isotherm accords with the Freundlich adsorption model.
【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O611.4

【参考文献】