Abstract

The congener polychlorinated biphenyls (PCBs) are one of the of persistent organic pollutant compounds that increase lifestyle-related diseases, such as diabetes, obesity, and cancer. So, 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153), which is one of the most common PCB contaminants in nature, was selected as a model compound to study the photocatalytic degradation of Fe3O4@SiO2@TiO2 core-shell structure. In this work, Fe3O4@SiO2@TiO2 nanocomposite was synthesized and characterized using transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), energy-dispersive X-ray (EDS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM) techniques. Then, the effect of parameters such as catalyst dosage, initial concentration of PCB 153, solution pH, amount of H2O2, and kind of co-solvent on photocatalytic degradation of PCB 153 by the synthesized nanocomposite was investigated. The high degradation efficiency of Fe3O4@SiO2@TiO2 nanocomposite, which was 96.5%, was obtained at 4 g/l of the catalysts, 4 ppm of PCB 153, pH 5, 20 mM H2O2, 2 h of reaction time, and acetone as a cosolvent. Also, the rate of mineralization for Fe3O4@SiO2@TiO2 nanocomposite with H2O2 and UV-LED irradiation was 75.3% which had a significant efficiency compared to control experiments. Moreover, the mentioned photocatalysts are possible to be reused through exposing to external magnetic field, with insignificant decrease in the catalytic activity even after 6 cycles. The photocatalytic degradation process has an effective and environmental friendly effect on the degradation of organic pollutants.