Degradation of Malachite Green Dye by Solar Irradiation Assisted by TiO 2 Biogenic Nanoparticles Using Vaccinium corymbosum Extract

The green synthesis of metal oxide nanoparticles (NPs) offers an alternative to chemical procedures, which can be harmful to human health due to exposure to hazardous substances and harsh synthesis conditions. The following work synthesized titanium dioxide nanoparticles (TiO 2 NPs) using a green synthesis method. As a precursor, food-grade TiO 2 was used with blueberry extract. This approach makes the process safer, cheaper, and simpler, requiring minimal effort to achieve effective TiO 2 NP synthesis. The TiO 2 NP characterization was performed by solid-state techniques, such as Ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). According to the XRD diffractograms, TiO 2 NPs were obtained in the anatase phase with incidence peaks of 25.28 (101). TEM confirmed their pseudo-spherical shape with an average size of 170 nm. The 3.2 eV bandgap of TiO 2 NPs enables UV absorption, making them ideal for efficient photocatalytic degradation under sunlight. On the other hand, the photocatalytic activity of TiO 2 NPs was examined using malachite green (MG) dye as a pollutant model under direct sunlight. After 30 min, a degradation of 94% was achieved. The kinetic analysis identified parabolic diffusion and modified-Freundlich kinetics as primary mechanisms, emphasizing diffusion and adsorption in electron transfer. The main reactive oxygen species (ROS) involved in the photodegradation of MG dye were h + and OH • .