tio2/fe3o4 nanocomposite photocatalysts for enhanced photo-decolorization of congo red dye

tio2 /fe3o4 nanocomposites with various tio2:fe3o4 ratios were synthesized by an ultrasonic-assisted deposition-precipitation method and their uv-light decolorization of congo dye and magnetic separation were investigated. the nanocomposite samples were characterized by scanning electron microscopy (sem), powder x-ray diffraction (xrd), surface area analayzer (bet) and fourier transform infrared spectroscopy (ftir). the effect of tio2 /fe3o4 ratio on the photocatalytic activity and magnetic property of the nanocomposites was studied by comparing their decolorization curves and magnetism in the presence of magnet, respectively. the results revealed that the decolorization efficiency and the chemical oxygen demand (cod) removal of tio2 /fe3o4 nanocomposite with the ratio of 24/1 reached about 95% and 50%, respectively, within 60 min at room temperature. however, this sample showed the least magnetism. the tio2 /fe3o4 nanocomposites with the ratio of 16/1 showed the optimum magnetism and  hotodecolorization activity. also, the ability of synthesized nanocomposites in holding the adsorbed congo red dye on their surface was investigated.