Facile preparation of Fe3O4/mesoporous TiO2 nanoparticles shell on polystyrene beads and its effective absorption of cyanobacteria in water

In this letter, a facile method were used to prepare raspberry-like polystyrene-magnetite mesoporous titanium dioxide particles (PS-Fe3O4/mTiO(2)), which have potential application in handling pollutants floated on water such as cyanobacteria. This method involved the dispersion polymerization of styrene with Fe3O4/mTiO(2) nanoparticles modified by vinyltrimethoxysilane (VTMS) where 2, 2-azobisisobutyronitrile (AIBN) was used as initiator. When VTMS was applied, the Fe3O4/mTiO(2) nanoparticles loaded on the surfaces of PS beads homogeneously while weak loading occurred when VTMS was absent. The homogeneous loading resulted from the fact that VTMS could strengthen the force between PS beads and Fe3O4/mTiO(2) nanoparticles, meaning that VTMS was effective in loading the Fe3O4/mTiO(2) nanoparticles on PS beads. The as-prepared materials had high hydrophobic surfaces, and low density. After the resulting composite was loaded on the surfaces of cyanobacteria and separated by magnetic field, the magnetic properties of Fe3O4 was retained, indicating that this composite could remove cyanobacteria in water effectively. Our results provide insight into the water-treatment of pollutants.