Photocatalytic dye degradation using nickel ferrite spinel and its nanocomposite

Coloured wastewater is a major issue of today for human health and ecology. Among all available processes such as physical, chemical, biological and electrochemical methods, photocatalysis can be a promising solution because of its ability to degrade colour-causing compounds completely by converting them into simpler molecules (H₂O, CO₂) depending on dye structure. In this work, NiFe₂O₄ was synthesized by the co-precipitation method. Furthermore, the composites of NiFe₂O₄ with TiO₂ were synthesized by varying amounts of TiO₂. The spinel and composites were characterized by XRD, ZETA analysis and UV-DRS. Their photocatalytic activities were investigated using the photocatalytic degradation of reactive turquoise blue 21 (RB 21) dye as model pollutants under sunlight. The increased absorption of the visible light and the enhanced separation of the electron-hole pairs due to the relative energy band positions in NiFe₂O₄ and TiO₂ are considered as the main advantages. Our results showed that NiFe₂O₄-based nanocomposites could be used as an effective and magnetic retrievable photocatalyst.