Photocatalytic activity of magnetically separable TiO2/SiO2/Fe3O4 composite for dye degradation

In the present study, a magnetically separable photocatalyst (TiO2/SiO2/Fe3O4) has been prepared and used for the photooxidation of methyl orange (MO) dye. The effects of various reaction conditions such as dye concentration, catalyst dose, and pH on the reaction rate were investigated to enhance the photooxidation process. Thephotocatalytic oxidation of MO was found to follow half-order kinetics. The optimum reaction conditions were found to be a 2000 ppm TiO2 catalyst dose in an acidic medium. A higher catalyst load had no effect on the degradation rate. The dye concentration negatively affected the reaction rate because of the reduced light transmittance inside the photoreactor. The catalyst could be reused several times with nearly the same activity and thus the final cost of the treatment process could be reduced. © 2011 The Society of Chemical Engineers, Japan.