Green synthesis of TiO2 nanoparticle : its characterization and potential application in Zoxamide photodegradation.

This article reports the green synthesis of titanium dioxide nanoparticles (TiO2 NPs) from aqueous leaf extract of Trema Orientalis (L) and its effectiveness in photodegradation process of zoxamide under UV irradiation(λ max ≥ 250 nm). Titanium (IV) isopropoxide act as the precursor and leaf extract act as the reducing agent. The synthesized TiO2 NPs are confirmed by the powder X-ray diffraction (XRD) analysis and the crystalline size was calculated by the Scherrer’s formula(52nm) and as well as Williaman-Hall(W-H) equation(59 nm). The Dynamic Light Scattering (DLS) analysis shows the stability and particle size of approximately 88-94 nm of the synthesized TiO2 NPs. The Fourier Transform Infrared Spectroscopy (FTIR) analysis confirms the presence of various functional groups in the synthesized NPs. The UV absorption wavelength observed at the peak of 351 nm and the calculated energy band gap is found to be 3.27eV. The surface morphology of the synthesized TiO2 NPs is determined by using Scanning Electron Microscopy (SEM). The rate of photodegradation of zoxamide in acetonitrile/water solvent system followed pseudofirst- order kinetics, and calculated half-lives were found to be in the range of 2.33 -10.46 h. From this study, one photoproduct was isolated and characterized based on column chromatography, mass spectral data, and X-ray crystallography. The isolated photoproduct was identified as 3,5-dichloro-4 methyl benzoic acid. The plausible mechanistic pathway of the formation of photoproducts is also depicted. Langmuir– Hinshelwood (L–H) kinetic model was proposed for the rate equation of the zoxamide photodegradation in the presence of TiO2 NPs under UV irradiation.