4. Conclusions
Photocatalytic Fe3O4/SiO2/TiO2 composites were prepared by
layer-by-layer chemical route. The reagents involved in the synthesis
of photocatalysts (Fe3O4/SiO2/TiO2) were inexpensive and suitable
for a large-scale production. PAA treatment of the silica
surface was important for the deposition of titania crystals. After
calcination, TiO2 catalysts connected to the silica surface through
covalent bonds and the loading of TiO2 can be easily controlled
during the preparation process. The composite photocatalyst could
remove more than 80% of RhB by adsorption and photodegradation
after 120 min UV irradiation. Comparing to pure TiO2, the Fe3O4/
SiO2/TiO2 photocatalysts can be efficiently separated from liquid
by using external magnetic field.