Exploration of Methylene Blue Degradation over ZnO Nanorods Mechanism using Scavenging Reagents

Hierarchical porous flower-like ZnO structures containing ZnO nanorods were successfully synthesizedby precipitation process. The structure containing high aspect ratio nanorods was revealed by scanning electron microscopy(SEM). The EDS analysis revealed the ZnO nanostructures formation as confirmed by the Zn and O peaks. The Fourier-transform infrared spectroscopy(FTIR) spectrum indicated the Zn – O bond vibrational frequency. The typical hexagonal wurtzite ZnO nanostructure with 15 nm crystallite size and the characteristic parameters was perceived from the X-ray diffraction(XRD) data. A 10.13 m².g-1 surface area, 10.05 cm3/g pore volume and 18.25 nm pore diameter were estimated using nitrogen adsorption analysis. Bandgap energy of 3.229 eV was calculated from the optical analysis data. Under ultraviolet light irradiation, the prepared nanoparticles has effectively decolorized the methylene blue dye. The reaction obeyed the pseudo-first-order kinetics, and the degradation mechanism was proposed using radicals scavengers to determine the species involved in the photodegradation process such as isopropanol, p-benzoquinone, and dimethyl sulfoxide. The reactive oxygen atom in the mechanism of photodegradation , and the recyclability of ZnO photocatalysts were studied.