The Fabrication of Magnetically Recyclable La-Doped TiO2/Calcium Ferrite/Diatomite Composite for Visible-Light-Driven Degradation of Antibiotic and Disinfection of Bacteria

摘要

Powdery photocatalyst has been deeply studied due to its great potential in water treatment, yet its low recyclability is the bottleneck hindering its practical application. In this work, magnetically recyclable lanthanum-doped TiO2/calcium ferrite/diatomite (La-TCD) ternary composite was synthesized by sol-gel method. The physicochemical properties of this material were characterized and studied, and the photocatalytic property was evaluated by the decomposition of antibiotic oxytetracycline (OTC) and disinfection of bacteria Escherichia coli under visible light irradiation. The formation of heterojunction between La-doped TiO2 and calcium ferrite hindered the recombination of photo-induced charge carriers and improved the photocatalytic activity. Besides, the photodecomposition of OTC was enhanced by the high adsorption ability of substrate diatomite, in other words, the adsorption and decomposition synergistic behavior between catalyst and diatomite. The optimal La doping amount, as well as composite dosage, was determined. The composite could simply be recovered from waterbody by an external magnet, and the repetition tests indicated no obvious decrease of photoactivity after five cycles. Above all, this composite presented good potential to be applied in wastewater remediation process.