Photocatalytic degradation of tetracycline over Ce-doped TiO2@SiO2@Fe3O4 magnetic material

This study analyzed the removal effect of tetracycline (TC) in an aqueous solution. The magnetic photocatalytic material Ce-TiO2@SiO2@Fe3O4 (y%Ce-TSF) with a core-shell structure was prepared using SiO2@Fe3O4 (SF) synthesized by a hydrothermal method as the carrier, as well as tetrabutyl titanate and cerium nitrate, acting as precursors. The composition, chemical structure, morphological characteristics, and magnetic intensity were measured. The results showed that Ce doping on TSF inhibited the growth of TiO2 crystals. More hydroxyl radicals (OH) could be generated during the photocatalytic reaction of the composite 5%Ce-TSF, which was conducive to the reaction process. TSF comprised a TiO2 shell, SiO2 interlayer, and Fe3O4 inner core. The magnetic response intensity of 5%Ce-TSF was broadened, making its photocatalytic activity stronger than that of TSF. Under visible light action, the removal rate of 5%Ce-TSF from 60 mg L-1 in 90 min was 93.21%, exceeding those of TSF and pure TiO2 by 1.57 and 1.98 times, respectively. Free-radical sacrificial agents (Triethanolamine (TEOA), propan-2-ol (IPA), l(+)-ascorbic acid (VC), potassium bromate (KBrO3), etc.) were also utilized to clarify the TC photocatalytic degradation mechanism. O2- and OH were found to play a dominant role in the catalytic process. This work provides new insight into organic waste photocatalytic degradation.