【作者】 侯荣；

【导师】 张慧；

【作者基本信息】 北京化工大学 ， 应用化学， 2009， 硕士

【摘要】 本文采用模板法合成了空心球结构的功能性材料——钴铁氧体磁性空心球,旨在为制备满足不同性能要求的磁性空心球提供一种简单绿色的合成方法,并对所制磁性空心球在蛋白质吸附和光催化领域的应用进行了探索研究。本论文的主要内容和创新点如下:以聚苯乙烯（PS）球为模板,以NaOH为沉淀剂,通过Co（NO₃）₂和FeCl₃在模板表面的共沉淀自组装合成了钴铁氧体前体包覆聚苯乙烯球,经500℃焙烧去除模板得到形貌与性能各异的钴铁氧体磁性空心球。采用XRD、FT-IR、TG-DTA、SEM、TEM、BET和VSM等表征技术,研究了反应pH值及模板尺寸对磁性空心球组成、磁学性能及形貌的影响。结果表明,随pH值的升高,磁性空心球的晶相趋于成为单一的钴铁氧体,且其比饱和磁化强度总体呈现增大趋势（22.7-43.8 emu/g）。首次发现模板尺寸对磁性空心球壳层粒子的形状和堆积方式有显著影响。在230-2300nm范围内,随模板尺寸的增大,所得磁性空心球壳层粒子的形貌特征表现为由球/棒形粒子杂乱堆积,经以棒形粒子为主垂直于球壳排布,到纺锤形粒子平铺于球壳堆积模式。以牛血清白蛋白（BSA）为模型蛋白,首次考察了不同尺寸钴铁氧体磁性空心球对蛋白质的吸附性能。结果表明,磁性空心球对BSA的吸附量为75.0-104.7 mg/g,其中尺寸～600nm的磁性空心球吸附量最大,这可能是由于该尺寸磁性空心球粒子的最可几孔径与BSA尺寸相近所致。以磁性空心球为基质,采用溶胶-凝胶法在表面包覆光催化活性层TiO₂,构筑TiO₂修饰磁性空心球。结果表明,所得TiO₂修饰磁性空心球由钴铁氧体和锐钛矿型TiO₂组成,具有铁磁性,比饱和磁化强度σ_s为1.56 emu·g^-1,用于光催化降解甲基橙速率常数κ可达1.5×10^-3min^-1,与类似组成的核-壳结构纳米粒子的光催化活性结果相当。考虑到磁性空心球密度低,分散性好的特点,其应用前景将更为广阔。更多还原

【Abstract】 In the present work,monodispersed magnetic hollow spheres are prepared using a template-assisted method,which is facile and eco-friendly route for the fabrication of magnetic hollow spheres to meet different demands.In addition,the adsorption property of magnetic hollow spheres for bovine serum albumin and their extended applications in photocatalysis are also primarily investigated.The main content and novelty of this thesis are detailed as follows:Monodispersed cobalt ferrite magnetic hollow spheres are prepared by a simple co-precipitation of ferric chloride and cobalt nitrate over polystyrene spheres in the presence of aqueous NaOH solution followed calcinations.XRD,FT-IR,TG-DTA,SEM,TEM,BET and VSM techniques are used to investigate the influences of template sizes and pH conditions upon composition,magnetic properties and morphology of the magnetic hollow spheres.The results show that the pH value is a key point in regulating the composition of magnetic hollow spheres.The as-prepared magnetic hollow spheres,whose saturation magnetization values fall in 22.7-43.8 emu/g,are mainly composed of cobalt ferrite phase.Moreover,it is firstly observed that the cobalt ferrite nanoparticles constructing the hollow spheres wall present prominently different shape and stacking mode depending on the template size.The adsorption properties of the cobalt ferrite magnetic hollow spheres with different sizes for bovine serum albumin（BSA） are firstly investigated.The results show that the adsorption amount of bovine serum albumin on magnetic hollow spheres is 75.0-104.7mg/g.The maxium adsorption amount is observed on the middle-sized magnetic hollow sphere（～600nm）,which is probably originated from the matchable size of the pore diameters of the magnetic hollow spheres and the BSA molecules.Using magnetic hollow spheres as substrates,photoactive titania are coated on their surface via a sol-gel method,in order to fabricate the photoactive titania modified magnetic hollow spheres.The obtained titania modified magnetic hollow spheres are mainly composed of anatase and cobalt ferrite,showing ferromagnetic,and considerable photocatalytic degradation activity for methyl orange(k = 1.5x10^-3 min^-1, which is comparable with that of the solid core-shell structured nanoparticles).Taking into account the low density and good dispersion in water,it can be expected that magnetic hollow spheres may have greater potential in applications.更多还原