功能化磁性纳米复合材料的制备及其对Pb（Ⅱ）和Cr（Ⅵ）的选择性去除研究

发布时间：2018-06-27 12:35

本文选题：Fe_3O_4@SiO_2 + 功能化　；参考：《浙江大学》2015年硕士论文

【摘要】：利用新颖、高效和易分离的功能化Fe304磁性纳米材料去除水中的重金属,已越来越受到研究者的关注。本文采用化学氧化法将问苯二胺单体(mPD)和对苯二胺邻磺酸单体(SP)共聚包覆在纳米Fe304@Si02表面上,制备出氨基、亚氨基、磺酸基等修饰的功能化磁性纳米复合材料(Fe3O4@SiO2-mPD/SP).通过改变mPD/SP单体的比例进行共聚包覆,分别筛选出针对Pb(Ⅱ)和Cr(Ⅵ)去除的Fe3O4@SiO2-mPD/SP,并通过TEM、XRD、FTIR等手段对功能化改性前后的磁性纳米复合材料进行表征,了解其形貌、结构、化学组成、磁性特性及耐酸耐碱性等特征；考察了Fe3O4@SiO2-mPD/SP对Pb(Ⅱ)、Cr(Ⅵ)的选择性吸附性能和影响因素,深入探讨了Fe3O4@SiO2-mPD/SP对Pb(Ⅱ)、Cr(Ⅵ)重金属离子的吸附机理；最后探索了Fe3O4@SiO2-mPD/SP的分离和重复利用性。通过X射线衍射、透射电镜、红外、热重分析等表征手段,考察了功能化改性前后磁性纳米复合材料的形貌、结构、化学组成和磁性特性。通过表征发现Fe3O4@SiO2-mPD/SP保持了Fe3O4的尖晶石结构,具有良好的热稳定性和耐酸耐碱性,且磁响应强度大,仅需30s就可从废水中有效分离。磁性纳米Fe3O4颗粒主要为粒径20-30 nm的均匀球形颗粒,包裹在Fe3O4@SiO2表面的聚合物为mPD-SP的共聚物,而不是]mPD-mPD聚合物和SP-SP聚合物的简单混合。通过调整mPD/S P比例对重金属离子去除效果的研究,得出Pb(Ⅱ)和Cr(Ⅵ)去除的最优mPD/SP共聚比例分别为95：5和50：50,Fe3O4@SiO2-mPD/SP(95:5)和Fe3O4@SiO2-mPD/SP(50:50)对Pb(Ⅱ)和Cr(Ⅵ)的饱和吸附量分别为83.23和119.06 mg g-1。Fe3O4@SiO2-mPD/SP(95:5)对Pb(Ⅱ)的吸附速率较快,反应5min即可达到吸附平衡；而Fe3O4@SiO2-mPD/SP(50:50)对Cr(Ⅵ)的吸附在前30 min较快,但需要6 h左右才逐渐达到吸附平衡。Fe3O4@SiO2-mPD/SP(95:5)和Fe3O4@SiO2-mPD/SP(50:50)对Pb(Ⅱ)和 Cr(Ⅵ)的吸附过程均符合准二级动力学方程和Freundlich模型；热力学研究表明,Fe3O4@SiO2-mPD/SP(95:5)和Fe3O4@SiO2-mPD/SP(50:50)对Pb(Ⅱ)和 Cr(Ⅵ)的吸附过程均为自发的吸热过程；溶液pH值对Fe3O4@SiO2-mPD/SP(95:5)和Fe3O4@SiO2-mPD/SP(50:50)的吸附作用均有显著的影响；而天然有机物、竞争性离子对Fe3O4@SiO2-mPD/SP(95:5)和Fe3O4@SiO2-mPD/SP(50:50)的吸附作用无显著影响；Fe3O4@SiO2-mPD/SP(95:5)和Fe3O4@SiO2-mPD/SP(50:50)均具有较好的分离再生和循环使用性能。功能化磁性纳米复合材料Fe3O4@SiO2-mPD/SP(95:5)和Fe3O4@SiO2-mPD/SP(50:50)可分别从多种重金属离子共存的废水中选择性地将Pb(Ⅱ)和Cr(Ⅵ)高效去除。通过测量Fe3O4@SiO2-mPD/SP(95:5) 和 Fe3O4@SiO2-mPD/SP(50:50)吸附Pb(Ⅱ)和Cr(Ⅵ)前后溶液pH值的变化,对吸附Pb(Ⅱ)和Cr(Ⅵ)前后的功能化磁性纳米Fe3O4材料进行FTR和XPS表征,考察Fe3O4@SiO2-mPD/SP(50:50)吸附Cr(Ⅵ)过程中剩余总Cr和Cr(Ⅵ)浓度随吸附时间的变化,可以得出Fe3O4@SiO2-mPD/SP对 Pb(Ⅱ)和Cr(Ⅵ)的吸附机理主要包括：离子交换、络合吸附、氧化还原反应、静电吸引和物理吸附等过程。其中Fe3O4@SiO2-mPD/SP(95:5)对Pb(Ⅱ)的吸附过程,络合吸附占主导作用,而Fe3O4@SiO2-mPD/SP(50:50)对 Cr(Ⅵ)的吸附过程,络合吸附和氧化还原反应占主导作用。
[Abstract]:The use of novel, efficient and easy separation functional Fe304 magnetic nanomaterials to remove heavy metals in water has attracted more and more attention. In this paper, a chemical oxidation method was used to encapsulate two amines (mPD) and phenylene two amine o sulfonic acid monomer (SP) on the surface of nanoscale Fe304@ Si02 to prepare amino, subamino, sulfonic acid groups and so on. Functionalized Magnetic Nanocomposites (Fe3O4@SiO2-mPD/SP). By modifying the proportion of mPD/SP monomers to encapsulate, the Fe3O4@SiO2-mPD/SP for the removal of Pb (II) and Cr (VI) was screened, and the Magnetic Nanocomposites before and after functional modification were characterized by TEM, XRD, FTIR and so on, and their morphology, structure and chemistry were understood. The composition, magnetic properties, acid resistance and alkali resistance, the selective adsorption properties and influence factors of Fe3O4@SiO2-mPD/SP on Pb (II), Cr (VI), and the adsorption mechanism of Fe3O4@SiO2-mPD/SP on Pb (II), Cr (VI) heavy metal ions, and the separation and reutilization of Fe3O4@SiO2-mPD/SP are explored. Through X ray diffraction, through the X-ray diffraction, and through the X ray diffraction. The morphology, structure, chemical composition and magnetic properties of the Magnetic Nanocomposites before and after functional modification were investigated by means of electron microscopy, infrared and thermogravimetric analysis. It was found that Fe3O4@SiO2-mPD/SP maintained the spinel structure of Fe3O4, and had good thermal stability, acid resistance and alkali resistance, and the magnetic response intensity was great, only 30s could be used. The magnetic nano Fe3O4 particles are mainly homogeneous spherical particles with a particle size of 20-30 nm, and the polymer of the Fe3O4@SiO2 surface is a copolymer of mPD-SP, not a simple mixture of]mPD-mPD and SP-SP polymers. By adjusting the ratio of mPD/S P to the removal of heavy metal ions, Pb (II) and Cr (VI) are obtained. The optimal mPD/SP copolymerization ratio is 95:5 and 50:50 respectively. The adsorption capacity of Pb (95:5) and Fe3O4@SiO2-mPD/SP (50:50) to Pb (II) and Cr (VI) is 83.23 and 119.06 mg g-1.Fe3O4@SiO2-mPD/SP (95:5) has a faster adsorption rate. The adsorption of (VI) is faster in the front 30 min, but it takes about 6 h to gradually reach the adsorption equilibrium.Fe3O4@SiO2-mPD/SP (95:5) and Fe3O4@SiO2-mPD/SP (50:50) for Pb (II) and Cr (VI) adsorption processes that conform to the quasi two kinetic equation and Freundlich model. The adsorption process of and Cr (VI) were both spontaneous endothermic processes, and the pH value of the solution had a significant effect on the adsorption of Fe3O4@SiO2-mPD/SP (95:5) and Fe3O4@SiO2-mPD/SP (50:50), while the natural organic matter, the competitive ions had no significant influence on the adsorption of Fe3O4@SiO2-mPD/SP (95:5) and Fe3O4@ SiO2-mPD/SP (50:50); P (95:5) and Fe3O4@SiO2-mPD/SP (50:50) have good separation and recycling performance. Functional magnetic nanocomposites, Fe3O4@SiO2-mPD/SP (95:5) and Fe3O4@SiO2-mPD/SP (50:50), can selectively remove Pb (II) and Cr (VI) from a variety of heavy metal ions. By measuring Fe3O4@SiO2-mPD/SP (95:5) The changes in the pH value of the solution before and after the adsorption of Pb (II) and Cr (VI) with Fe3O4@SiO2-mPD/SP (50:50) and the adsorption of Pb (II) and Cr (VI) on the functional magnetic nanoscale Fe3O4 materials before and after the adsorption of Cr (VI) are characterized by FTR and XPS, and the changes in the concentration of residual total and (VI) in the process of Fe3O4@SiO2-mPD/SP (50:50) adsorption (VI) can be obtained. The adsorption mechanism of /SP on Pb (II) and Cr (VI) mainly includes the processes of ion exchange, complex adsorption, redox reaction, electrostatic attraction and physical adsorption. The adsorption process of Fe3O4@SiO2-mPD/SP (95:5) to Pb (II), the dominant effect of complex adsorption, and the adsorption process of Fe3O4@ SiO2-mPD/SP (50:50) to Cr (VI), complex adsorption and oxidation The primary reaction is dominant.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;X703

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