title: Facile synthesis of ordered magnetic mesoporous gamma-Fe2O3/SiO2 nanocomposites with diverse mesostructures.
abstract: On the basis of a sol-gel process, a facile, low cost, and one-step approach for preparing ordered magnetic mesoporous gamma-Fe(2)O(3)/SiO(2) nanocomposites by an evaporation-induced self-assembly (EISA) approach is presented. Various mesostructured silica materials (P6mm or Im3m) incorporated with different amounts of iron oxide (n(Si)/n(Fe) = 9/1, 8/2, 7/3, respectively) were synthesized and characterized by XRD, TEM, N(2)-sorption analyses, and superconducting quantum interference device (SQUID) magnetometer. The HCl-leaching experiments together with TEM micrographs and nitrogen sorption analysis suggested that most of the gamma-Fe(2)O(3) domains of several nanometers were embedded in the silica walls, rather than dispersed in the mesopores, which could cause the significant pore clogging reported in some studies. The release behaviors of lysozyme from these magnetic porous nanocomposites were investigated for the possible application of drug targeting and control release. The influence of iron precursors was also studied and a possible mechanism was proposed. The hydrolysis of Fe(3+) ions under weakly acidic conditions and the induced formation of Si-O-Fe bonds may account for the synthesis of this kind of nanocomposite. These multifunctional nanostructured materials would have a wide range of applications in toxin removal, catalysis, waste remediation, and biological separation as well as novel drug-carrier technologies.
authors.affiliation: Lab for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, People's Republic of China.
authors.forename: Yangang
authors.initials: Y
authors.lastname: Wang
authors.forename: Jiawen
authors.initials: J
authors.lastname: Ren
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Liu
authors.forename: Yanqin
authors.initials: Y
authors.lastname: Wang
authors.forename: Yun
authors.initials: Y
authors.lastname: Guo
authors.forename: Yanglong
authors.initials: Y
authors.lastname: Guo
authors.forename: Guanzhong
authors.initials: G
authors.lastname: Lu
mesh_terms: D000327:Adsorption; D005290:Ferric Compounds / Q000737:chemistry*; D008280:Magnetics; D046529:Microscopy, Electron, Transmission; D009113:Muramidase / Q000737:chemistry / Q000302:isolation & purification; D053761:Nanocomposites / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D044367:Phase Transition; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D012822:Silicon Dioxide; D009113:Muramidase