Photocatalytic degradation of recalcitrant micropollutants by reusable Fe3O4/SiO2/TiO2 particles

Abstract

Photocatalysis promotes the degradation of contaminants in water, transforming them into by-products with lower or no toxicity. The photocatalysts can be applied in suspension or immobilized onto a support. The aim of using the immobilized form against the suspension form is that the costly extra final filtration process can be avoided, which is particularly important in water decontamination. This work reports on reusable Fe3O4/SiO2/TiO2 particles and the assessment of their photocatalytic activity on the degradation of methylene blue (MB), ciprofloxacin (CIP), norfloxacin (NOR) and ibuprofen (IBP). To achieve the most efficient photocatalyst it is necessary to determine the optimal thermal treatment parameters therefore, the Fe3O4/SiO2/TiO2 particles were calcined at different temperatures (500 °C and 600 °C) and times (30 min and 60 min). Higher degradation rates were achieved with calcination at 600 °C, reaching a total degradation of CIP, NOR, and MB, and half of IBP. The reuse of the magnetic particles is an economic and eco-friendly way to treat polluted water. The produced Fe3O4/SiO2/TiO2 particles showed a remarkable photocatalytic degradation of recalcitrant micropollutants, without significant efficiency loss after five uses. In addition, no other works reporting on the degradation of recalcitrant micropollutants using similar magnetic particles were found in the literature.