Sol-gel synthesis of ferrites nanoparticles and investigation of their magnetic and photocatalytic activity for degradation of reactive blue 21 dye

Abstract

Nanoferrites having excellent electromagnetic properties, great permeability, a good electromagnetic wave absorbing material, are widely used in information storage systems, the field of magnetic fluid technology and microwave devices and the like. However, it has attracted much attention, for their possibility of various substitution in lattice cell of spinel ferrite (AB2O4), can significantly improve the electromagnetic, catalytic, biologic of the ferrite properties. In this research work, we investigated the substitution of the Nickel Zinc ferrite by rare earth. we studied Ni0.4Zn0.6Fe1.9-xAl0.1GdxO4 (x = 0 and x = 0.1) afterwards named NZF-Al (NZFe-Al0.1Gdx for x = 0) and NZF-AlGd (NZFe-Al0.1Gdx for x = 0.1). These two compounds were prepared using sol-gel auto-combustion synthetic route, from precursors of metal nitrates, citric acid, ethylen-glycool and ammonia. The X-Ray patterns of the prepared powder have confirmed the structure of cubic spinel structure with a space group Fd-3 m (N° 227). The morphology of the samples was investigated by Scanning Electron Microscopy (SEM) and confirmed the nearly spherical nanoparticles with an average particle size of 63 and 41 nm, respectively, for samples with x = 0 and x = 0.1. It should be noted that the substitution of Fe3+ by Gd3+ does not change its crystal structure but increasing the Curie temperature of the sample from 339 K to 436 K. On the other hand, spinel ferrite nanoparticles have a significant photo-response in the visible light region with an excellent photochemical stability. They were also found to be very efficient in removing a wide variety of organic and inorganic contaminants. Therefore, the degradation of the reactive blue (RB-21) dye was studied in the presence of ferrite nanoparticles as a catalyst. The results demonstrated the high efficiency of ferrite nanoparticles in the degradation process. The catalyst can be easily recovered and recycled by simple magnetic separation.