Visible light induced photocatalytic degradation of methylene blue dye by using Mg doped Co-Zn nanoferrites

Abstract

Spinel nanoferrites are used by researchers in past years in various fields of applications like high-frequency applications, electronics, microwave devices and as a photocatalyst. Being very porous and having a low specific surface area, these nanomaterials are here used for the degradation of methylene blue dye using a heterogeneous adsorption photocatalytic process. Mg2+ substituted Co-Zn nano ferrite particles with composition Co0.5Zn0.5MgxFe2-xO4, where x = 0.25–1.0 with a step size of 0.25, were prepared using a chemical route named citrate precursor technique and various characterization of the samples was performed using Scanning electron microscopy (SEM), X-ray powder diffractometry (XRD), UV visible spectroscopy, Fourier infrared spectroscopy technique (FT-IR) for investigating the structural and optical properties. XRD spectra showed reflection peaks indexed to (220), (222), (400), (422), (511) and (440) dictating the cubic structure of the nanoferrite samples and one characteristic peak at (311) corresponding to the single-phase spinel cubic structure of the synthesized nanoferrite material. The materials were found to have good magnetic properties with saturation magnetization in the range 52.15 to 28.24 emu/g. A visible light source was used to degrade the methylene blue (MB) dye from water using a photocatalytic mechanism by creating a Fenton-type system. Almost complete degradation of MB dye was observed in one hour of visible light irradiation for Mg2+ concentration x = 1.0. Also, the degradation process of dye was found to have a pseudo first order kinetics model for all the synthesized samples. Hence, it can be confirmed that Mg substituted Co-Zn nanoferrites can act as an efficient catalyst for water purification by photocatalytic mechanism without any harm to the environment.