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

Abstract

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.