Green synthesis of TiO₂ nanoparticles using Beta vulgaris extract and the evaluation of their photocatalytic and antibacterial activity

This study presents the eco-friendly synthesis of TiO₂ nanoparticles (TiO₂-NPs) using Beta vulgaris (beetroot) extract. The material undergoes comprehensive characterization through XRD, Raman analysis, FTIR, BET, SEM, and TEM techniques. XRD analysis reveals a well-defined pure anatase phase, while TEM analysis confirms an average particle size of approximately 12 nm for the TiO₂-NPs. The photocatalytic performance is evaluated using methylene blue dye under direct sunlight. Results indicate that TiO₂-NPs exhibit high effectiveness as a photocatalyst, achieving a degradation efficiency of 91.41% within 195 min of sunlight exposure. Kinetic analysis against pseudo-first-order kinetics shows excellent fitting of experimental data with an R² value of 0.99, indicating strong data correlation. The theoretically calculated half-life is 54.69 min, with a normalized rate constant (k_app) of 1.267 min⁻¹ g⁻¹. Furthermore, the reusability assessment demonstrates that the retained photocatalytic activity of TiO₂-NPs even after three cycles of photodegradation was the same. Additionally, antibacterial assays reveal moderate activity against gram-negative bacterial strains such as E. coli and Pseudomonas aeruginosa, while no activity is observed against gram-positive bacterial strains.