Green synthesized TiO2 nanoparticles from herbal extracts for photocatalytic dye degradation: mechanistic insights into nano-geochemical interfaces.

The integration of green-synthesized nanomaterials with environmental processes offers promising strategies for mitigating anthropogenic contaminants in ecosystems. In this study, TiO2 nanoparticles were synthesized using aqueous extracts from four herbal plants: Curcuma longa, Ocimum basilicum, Plencranthus amboinicus, and Calotropis procera, representing an eco-friendly approach to nanomaterial fabrication. Comprehensive characterization using SEM, TEM, XRD, UV-Vis spectroscopy, FTIR spectroscopy, UV-DRS, and PL was employed to elucidate the morphology, crystallinity, and electronic properties of the nanoparticles. Microscopy-based analyses revealed distinct plant-mediated morphologies that strongly influenced photocatalytic performance in the degradation of Brilliant Green (BG) dye under sun-light irradiation, with Curcuma longa-derived TiO2 exhibiting the highest degradation efficiency. This work demonstrates how green synthesis, combined with advanced characterization, provides mechanistic insights into nano-geochemical interactions between nanoparticles and contaminants. The findings highlight the potential of plant-mediated TiO2 nanoparticles as sustainable photocatalysts for dye remediation and offer a model for designing eco-friendly nanomaterials to address broader environmental challenges.