Magnetic recyclable photocatalysts of Ni-Cu-Zn ferrite@SiO2@TiO2@Ag and their photocatalytic activities

Ag nanoparticles with different weight percentage loaded on Ni-Cu-Zn ferrite@SiO2@TiO2 composite were successfully prepared via sol-gel method. The effect of deposited amount of Ag nanoparticles on structural, magnetic and photocatalytic properties of the composite was investigated. XPS characterization confirmed that Ag nanoparticles deposited on the surface of Ni-Cu-Zn ferrite@SiO2@TiO2 composite. Particle size and shape of magnetic recyclable photocatalysts were observed using TEM, showing a core shell structure with an average particle size of 20 nm of Ag. Based on room temperature magnetic hysteresis curves, as 0.4 wt% Ag immobilized on Ni-Cu-Zn ferrite@SiO2@TiO2 composite revealed the maximum saturation magnetization of 39.9 emu/g. Photocatalytic degradation of Ni-Cu-Zn ferrite@SiO2@TiO2@Ag was carried out in methylene blue (MB) solutions illuminated under a 35-W Xe arc lamp and color temperature of 6000 K. The results revealed that 83.9% of MB was photodegraded for 0.4 wt% of Ag-loaded Ni-Cu-Zn ferrite@SiO2@TiO2. Moreover, it can be easily separated and recycled without significant loss of photocatalytic activity after being used five times. Compared to the conventional photocatalysts, the magnetic core-shell photocatalyst is suitable for large scale applications in industrial wastewater system. (C) 2016 Elsevier B.V. All rights reserved.