Preparation of magnetic photocatalysts from TiO2, activated carbon and iron nitrate for environmental remediation

Abstract

In this study different magnetic photocatalysts were prepared. Activated carbon (AC) and iron nitrate were used for the preparation of a magnetic support (Fe/AC). Different TiO2 contents were supported on the surface of Fe/AC to obtain the photocatalyst Ti/Fe/AC. Results obtained by XRD showed that the photocatalysts have Fe3O4, which confers magnetic property. The presence of carbon and TiO2 was confirmed by Raman and XRD. Scanning Electron Microscopy images showed clusters of TiO2 particles on the surface of Fe/AC. Results of X-ray fluorescence allowed the obtention of the levels of carbon, iron and titanium in the photocatalysts, which followed the expected trend. The results of reactions carried out in the presence of ultraviolet radiation showed that the magnetic photocatalysts removed from 50 to 96% of color ratio of Reactive Black (RB) in aqueous medium. The best efficiency for removal of total organic carbon (TOC) reached 90%. Sedimentation kinetics tests performed in the presence of magnetic field showed that nearly 92% of the photocatalysts could be rapidly separated from the aqueous medium, while pure TiO2 does not sediment efficiently. Results for the recovery and reuse of the photocatalysts for four consecutive reactions showed that they can be separated from the reaction medium in a simple and fast way, without significant losses of photocatalytic efficiency. These results showed that the prepared magnetic photocatalysts have excellent photocatalytic activity and can be easily recovered and reused, which implies the reduction of costs and increases the potential for scale up application.