Sintered NiFe₂O₄ Nanoparticles for the Photocatalytic Degradation of Malachite Green

The environmental contamination by hazardous pollutants, particularly Malachite Green (MG) dye from industrial activities such as the textile industry, poses a significant concern. This research investigates the production and application of NiFe2O4 nanoparticles for the photocatalytic degradation of MG dye. NiFe2O4 nanoparticles were synthesized via a hydrothermal method and sintered at various temperatures (500 °C, 600 °C, 700 °C, and 800 °C). Their structural and photocatalytic properties were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet–visible (UV–vis) spectroscopy. The NiFe2O4 sintered at 700 °C demonstrated optimal photocatalytic performance, achieving a degradation efficiency of 99% due to its superior crystallinity and phase purity. Additionally, the impact of NiFe2O4’s piezocatalytic properties on the degradation efficiency was explored by incorporating ultrasonic agitation during the photocatalytic process, which significantly enhanced the degradation efficiency. This improvement is attributed to the piezocatalytic-induced generation of reactive radicals. This study highlights the potential of NiFe2O4 as a dual-functional material for advanced photocatalytic applications, leveraging the combined effects of visible light irradiation and ultrasonic agitation to effectively degrade organic pollutants.