ZnO nanoparticles of rod-like architecture have excellent potential to be used in wastewater
treatment as a photocatalyst. They were synthesized by utilizing sonochemical/hydrationdehydration techniques using glutamine as a biotemplate. The effects of calcination
temperatures, that is, 300°C, 500°C, and 700°C, on the crystallinity, optical properties, and
photocatalytic activity of synthesized zinc oxide nanoparticles were investigated. X-ray
diffraction (XRD) results indicated that all calcinated samples have a crystalline hexagonal
wurtzite structure. Morphology and elemental compositions were investigated using field
emission-scanning electron microscopy with energy-dispersive X-ray spectroscopy. The XRD
and Fourier transform infrared (FTIR) spectra revealed that the samples were amorphous at
100°C; however, it changed into a crystalline structure amid the calcination process. Optical
properties were determined using a UV-visible reflection spectrophotometer and showed
abatement in the band gap with increasing annealing temperature. The progress of the
photocatalytic degradation was monitored by a UV-visible spectrophotometer, while the
mineralization ability was estimated by total organic carbon tests of ZnO-calcinated samples.
The effect of various operational parameters the photocatalytic efficiency and rate of dye
degradation was studied. High photocatalytic degradation of maxilon blue dye (GRL) was
found at pH 6.3.