Eco-Friendly TiO2 Nanoparticles: Harnessing Aloe Vera for Superior Photocatalytic Degradation of Methylene Blue

In recent years, the contamination of aquatic environments by organic chemicals, including dyes such as methylene blue (MB), Congo red, and crystal violet, has become an increasing concern, as has their treatment. In this work, titanium dioxide nanoparticles (TiO2 NPs) were studied for their photocatalytic performance by measuring the degradation of MB under UV light. TiO2 NPs were synthesized using two synthetic processes optimized in this study: a green method, namely leveraging the natural properties of Aloe vera leaf extract; and a conventional approach. The resulting NPs were thoroughly characterized using X-rays Diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET), UV–Vis and ζ-potential analysis. The TiO2 NPs synthesized by the green method demonstrated a degradation efficiency of (50 ± 3)% after 180 min, which was significantly higher than the (16 ± 3)% achieved by NPs synthesized through the conventional route. Moreover, the reaction rate constant for the green-synthesized TiO2 NPs was found to be approximately five times greater than that of the conventionally synthesized NPs. These results open up a new scenario in the pollution removal strategy research, using resources accessible in nature to synthesize NPs with high photocatalytic activity, which could also be useful for other applications, such as hydrogen production.