Potential of biosynthesized titanium dioxide nanoparticles towards wastewater treatment and antimicrobial activity

This study reports a green, sustainable, reliable, and cost-effective method for the biosynthesis of titanium dioxide nanoparticles (TiO₂NPs) using the leaf and stem extracts of Carissa opaca. The newly synthesized biogenic TiO₂NPs were confirmed and characterized using various analytical techniques, such as Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS), zeta potential, X-ray diffraction (XRD), inductively coupled plasma analysis (ICP), and scanning electron microscopy (SEM). Both the electron microscopy, i.e., SEM and HRTEM confirmed the spherical/hexagonal crystalline structure of TiO₂NPs with an average particle size range from 72.8 to 84.11 nm. These nanoparticles (NPs) exhibited aggregation and possessed a diverse array of functional groups on their surface. Biosynthesized TiO₂NPs showed excellent photocatalytic activity against methylene blue (MB) with decolorizing efficiency of 87.8% and 91.95%, whereas in case of methyl violet (MV), the decolorizing efficiency of 82.1% and 71.9% was observed with nanoparticles synthesized using leaf and stem extract, respectively. The newly synthesized NPs have also shown good antibacterial potential against Klebsiella pneumoniae and Staphylococcus aureus. This new biomimetic approach offers an economical and environmentally benign alternative for the removal of hazardous dyes and may find a place for antimicrobial applications.