组装法制备巯基改性磁性SBA-15

Preparation of sulfydryl functionalized magnetic SBA-15 by an assembling process

采用热分解法制备了单分散、平均粒径约15nm的锰铁氧体磁性纳米粒子。通过正硅酸乙酯与磁性纳米粒子表面油酸盐的配体交换将磁性纳米粒子锚定在SBA-15表面。并且将负载过程与巯基改性过程耦合制备了巯基改性的磁性SBA-15。考察了合成SBA-15过程中干燥方式对其结构和性质的影响,研究了负载磁性纳米粒子和巯基改性顺序对巯基改性磁性SBA-15的结构和性能的影响。结果表明,喷雾干燥法合成的SBA-15介孔孔壁较薄,但具有更大的比表面积、孔体积和平均孔径。以其为载体时磁性纳米粒子负载量更大,所得磁性SBA-15的饱和磁强度更高。当将巯基改性和负载磁性纳米粒子分为前后两步时,巯基改性SBA-15的表面疏水环境有利于吸附疏水磁性纳米粒子,所得磁性SBA-15负载磁性纳米粒子量更大,饱和磁强度更高。磁性纳米粒子粒径大于SBA-15孔径,其主要负载于SBA-15外表面,有利于得到介孔孔道通畅的磁性SBA-15。巯基改性的磁性SBA-15的孔体积介于0.56~0.6cm^3/g,比表面积介于353~432m^2/g,饱和磁强度最高达到0.91emu/g,可作为一种大容量的吸附材料用于吸附分离、药物缓释等领域。

Monodisperse and magnetic manganese ferrite nanoparticles with average diameter of 15nm were synthesized by a thermal decomposition method.The obtained magnetic nanoparticles were anchored onto the surface of SBA-15 through ligand exchange reaction of oleic acid and tetraethylorthosilicate.Meanwhile,sulfydryl functionalized magnetic SBA-15 was prepared by combining the anchoring process and surface modification of SBA-15.The influence of drying methods used during the synthesis of SBA-15 on its structure and properties was investigated.Effect of execution sequence of the anchoring and modification process on the structure and properties of sulfydryl functionalized magnetic SBA-15 was discussed.The result showed that SBA-15 prepared by spray drying showed thinner pore wall,higher specific surface area,pore volume and larger pore diameter,and could support more magnetic nanoparticles and thus exhibited stronger saturation magnetization.When the anchoring of the magnetic nanoparticles occurred on surface of the modified SBA-15,more nanoparticles were anchored on the surface of the SBA-15 due to a compatible hydrophobic chemical environment.Magnetic nanoparticles were mainly anchored onto the outside surface of SBA-15 because the pore diameters of the SBA-15 were smaller,which conserved the mesopores of SBA-15 unblocked.The obtained sulfydryl functionalized magnetic SBA-15 had pore volumes between 0.56cm3/g and 0.6cm3/g,specific surface area between 353m2/g and 432m2/g,and saturation magnetization of 0.91emu/g,which make it a high-capacity adsorbent for separation and drug release.