【作者】 周佳佳；

【导师】 丁明；

【作者基本信息】 安徽大学 ， 物理化学， 2010， 硕士

【摘要】 α-Fe2O3和Fe3O4是两种重要的铁的氧化物。α-Fe2O3由于其独特的性质,在化学传感器、催化剂、颜料、电池电极材料等诸多领域具有广泛的应用前景。Fe3O4因其独特的磁学性能和良好的生物相容性,运用于磁记录材料、磁性流体、药物的运输、免疫诊断等方面。对Fe3O4纳米颗粒表面修饰包覆改性,制备出Fe3O4纳米复合材料,既可以保留磁性,又具有新的特性,是近年来研究的热点。本论文主要研究了α-Fe2O3和Fe3O4纳米颗粒的制备并对Fe3O4表面进行包覆改性。主要研究内容如下：1.α-Fe2O3纳米棒和纳米立方体的制备及性能研究以FeCl3、尿素和表面活性剂十二烷基苯磺酸钠(DBS)为原料,首先通过水热体系得到α-FeOOH纳米棒,一方面通过直接煅烧前驱体的方法获得α-Fe2O3纳米棒,此过程产物保持了α-FeOOH的形貌；另一方面可在该水热体系中通过控制原料与DBS的物质的量之比,直接实现α-FeOOH→α-Fe2O3的转变,得到α-Fe2O3纳米立方体,从而同时实现了晶型以及形貌的转变。详细研究了表面活性剂含量对产物晶型和结构的影响,提出了可能的生长机理,同时对两种形貌的α-Fe2O3纳米颗粒的光学性能和磁学性能进行了初步研究。2.Fe3O4纳米颗粒的制备及其性能研究采用条件温和、易于控制、简单易行的液相合成方法,以FeSO4, (NH4)2CO3为原料,水为溶剂,加热回流直接得到磁性Fe3O4纳米颗粒,运用XRD、SEM,研究了反应温度、反应时间等因素的影响。当反应温度为80℃,时间为8h时成功制备出单晶准八面体Fe3O4纳米颗粒,由热重分析可知所制备的颗粒热稳定性良好,由磁性分析可知其饱和磁化强度高,达到81.24emu/g。3.Fe3O4/SiO2/壳聚糖纳米复合颗粒的制备及其性能研究壳聚糖具有特殊的生理活性、无毒、可生物降解、生物相容性好等优点,是纳米颗粒理想的修饰剂。本章采取的方法是首先对Fe3O4的表面进行SiO2包覆改性,再与壳聚糖复合,所制备的Fe3O4/SiO2/Chitosan纳米复合颗粒具有一定的磁性,便于分离,以重金属Cr6+溶液为模拟污染物,考察了其对Cr6+的吸附率,实验表明吸附率达到72.6%,制备的复合颗粒有望在污水处理等方面获得应用。4.Fe3O4／聚苯胺纳米复合材料的制备及其性能研究运用溶液聚合法在Fe3O4表面包覆聚苯胺,制备Fe3O4／聚苯胺纳米复合颗粒,对制备的复合物颗粒的形貌、结构和性能进行分析,由X射线衍射、红外测试证明两者不是机械混合,并讨论了Fe3O4含量对其磁性、热稳定性能以及吸波性能的影响,得知在复合材料当掺杂的含量为4.76%时,材料的吸波性能最佳,渴望作为吸波材料应用于实际。更多还原

【Abstract】 α-Fe2O3 and Fe3O4 are two important kinds of iron oxides.Forα-Fe2O3,because of its unique excellent properties, it is widely used as gas sensors,catalyst,pigment, electrode material,et.For Fe3O4,because of its magnetic property and biocompatibility, it is widely used in various fields,such as high-density magnetic recording media, ferrofluids,drug delivery,medical diagnosis,etc.Recent years,people become interested in the surface modification of Fe3O4,the composite nanoparticles not only keep the magnetic properties,but also have some new properties.In this dissertation, we have focused on the synthesis ofα-Fe2O3 and Fe3O4 nanoparticles,and doing some modification on the surface of Fe3O4. The detailed researches of the thesis are as follows:1.Synthesis ofα-Fe2O3 nanorods and nanocubes and their propertiesWe choosed FeCl3,CO(NH4)2 and soduim dodecyl benzene sulfonate(DBS) as raw materials,at first,α-FeOOH nanorods were synthesized,on one hand,α-Fe2O3 nanorods were obtained by calcination ofα-FeOOH nanorods,in this process,the product inherited the rod-like morphology;on the other hand,by controlling the amount of DBS in the hydrothermal system,we observed the direct transformation fromα-FeOOH toα-Fe2O3,what’s more,the structure developed to nanocubes.We deeply investigated the role of the surfactant in the phase and morphology,proposed a possible mechanism.The optical and magnetic properties of theα-Fe2O3 nanorods and nanocubes were also studied.2.Synthesis of Fe3O4 nanoparticles and their propertiesIn this article we adopted a simple,controllable and easy solution-phase approach, using FeSO4 and (NH4)2CO3 as raw materials, water as solvent, Fe3O4 nanoparticles were prepared by refluxing method.The effect of reaction temperature and time on the formation of the products had been described in detail using X-ray power diffraction (XRD) and scanning electron microscopy (SEM).When the reaction temperature reached 80℃and the time reached 8h, quasi-octahedral crystal Fe3O4 nanoparticles were successfully prepared.The nanoparticles were proved to be stable enough by thermogravimetry(TGA).Vibrating sample magnetrometer(VSM) was employed to investigate their magnetic properties,their saturated magnetization reached as high as 81.24 emu/g.3. Synthesis of Fe3O4/SiO2/Chitosan composite nanoparticles and their propertiesChitosan has special physiological activity,nontoxicity,biodegradability, biocompatibility,etc.It has abundant chemical groups and it is an ideal modification of nanoparticles.In this article,we first coated silica on the surface of Fe3O4 composite nanoparticles,then combied with chitosan.The prepared Fe3O4/SiO2/Chitosan nanoparticles had some magnetic property and they were easy to separate.Heavy metal ions(Cr6+) acted as contamination model,we investigated the adsorption efficiency of the prepared nanoparticles,the rusult showed that the efficiency reached 72.6% and they would have optical application in sewage disposal.4.Synthesis of Fe3O4/polyaniline composite nanoparticles and their propertiesIn this article,we modified the surface of Fe3O4 with polyaniline by using solution polymerization,prepared Fe2O4/polyaniline composite nanoparticles, the morphology, structure and properties of the products were investigated. We proved that Fe3O4 and polyaniline were not mechanically mixed by XRD and FTIR.The effects of the amount of Fe3O4 on the magnetic property, thermal stability and microwave absorption property were studied,we discovered that when the amount of the Fe3O4 reached 4.76%, the nanoparticles had excellent microwave adsorption property, they were eager to be one kind of ideal microwave adsorption materials.更多还原