Facile Synthesis of Bimodal Mesoporous Fe3O4@SiO2 Composite for Efficient Removal of Methylene Blue

A facile self-assembly synthetic procedure was exploited to fabricate mesoporous-silica-capped Fe3O4 mesoporous clusters, so-called bimodal mesoporous Fe3O4@SiO2 composites. Structural characterization demonstrated that the core of the Fe3O4 clusters is coated with a mesoporous silica shell of uniform size distribution. Moreover, unprecedentedly good tunability of the core size (180-1700 nm) and the shell thickness (20-75 nm) is achievable by changing the synthetic parameters. Application of the composite in the removal of the organic dye methylene blue (MB) from aqueous solution was examined. The composite exhibits excellent adsorption of methylene blue from aqueous solution (33.12 mgg(-1)) within 5 min and is easily regenerated by the photo-Fenton degradation reaction as a result of its high specific surface area, accessible pore channels, and good magnetic separation properties. This novel adsorbent promises extensive application in the practical removal of organic dyes.