Preparation of a new green magnetic Fe3O4 @TiO2-P25 photocatalyst for solar advanced oxidation processes in water

A novel green method has been investigated to obtain a magnetic recoverable photocatalyst. Fe3O4 particles formed in situ by aerial oxidative precipitation of aqueous Fe(II) in the presence of terephthalate were bonded to TiO2-P25 nanoparticles, giving rise to a coupled semiconductor heterostructure with superparamagnetic behavior at room temperature (Fe3O4 @TiO2-P25). The synthesis method is carried out in water at room temperature with almost full recovery and recycling of terephtalic acid. The prepared samples were fully characterized by XRD, TGA-DTA-MS, ATR-FTIR, WDXRF, TEM, SEM/EDX, N2 adsorption-desorption, elemental analysis, XPS, DRS, PL spectroscopy and SQUID. Photo-stability tests showed that Fe3O4 @TiO2-P25 does not undergo photodissolution under simulated solar radiation. The photocatalytic performance of Fe3O4 @TiO2-P25 was examined based on its ability to degrade aqueous metoprolol under UV–vis radiation in the presence of O2 and O3/O2. Also, the catalyst was successfully reused in six solar photocatalytic ozonation runs with negligible loss of photocatalytic activity.