Effect of large pore size of multifunctional mesoporous microsphere on removal of heavy metal ions

A novel multifunctional microsphere with a large pore size mesoporous silica shell (ca. 10.3 nm) and a magnetic core (Fe3O4) has been successfully synthesized via a facile two-step sol-gel method. In the synthesis process, CTAB was first dissolved in water to form spherical micelles, then added to the mixture in which Fe3O4@SiO2 was dispersed in ethanol, next dropping TEOS to form Fe3O4@SiO2@CTAB/SiO2 composites. This approach helps to form mesoporous silica shell with a large pore size, which is propitious to the modification of much more amino groups in order to enhance the adsorption capacity of heavy metal ions. The metal-loaded multifunctional microspheres can be easily removed from aqueous solution by magnetic separation and regenerated easily by acid treatment.