Maryam Heydari - Department of Nanomaterials and Nanocoatings, Institute for Color Science and Technology, Tehran, Iran
Mehrnaz Gharagozlou - Department of Nanomaterials and Nanocoatings, Institute for Color Science and Technology, Tehran, Iran
Mehdi Ghahari - Department of Nanomaterials and Nanocoatings, Institute for Color Science and Technology, Tehran, Iran

In this work, the Ni ferrite@SiO2 nanocomposite as an efficient magnetically separable environmental photocatalyst were prepared for decolorization of dyes as water pollutants. Magnetic nanocomposites of nickel ferrite nanoparticles uniformly dispersed in the silica matrix have been synthesized successfully by a sol–gel process using tetraethylorthosilicate (TEOS) and metallic nitrates as precursors and characterized with various techniques (e.g. XRD, FTIR, SEM, and TEM and VSM). The results indicated that the ferrite samples obtained by this method had the nanocrystalline pure single-phase spinel structure and good magnetic properties. TEM images showed spherical nanoparticles homogeneously dispersed in the silica network and were uniform in both morphology and particle size distribution with sizes of 10–15 nm. The results showed that the well-established silica network provided nucleation locations for NiFe2O4 nanoparticles to confinement the coarsening and aggregation of nanoparticles. The synthesized nanocomposite with adjustable particle sizes and controllable magnetic properties make the applicability of nickel ferrite even more versatile. The degradation of methyl orange dye as a water pollutant was investigated in the presence of hydrogen peroxide and nanoparticles. The most effective methyl orange degradation was achieved at pH 3.

Ni Ferrite@SiO2, Nanocomposite, Environmental photocatalyst, Decolorization, Water pollutant