Nano ZnO synthesis by modified sol gel method and its application in heterogeneous photocatalytic removal of phenol from water

[Display omitted] ▶ Nano ZnO was synthesized by modified sol gel and precipitation methods. ▶ The average particle size is 15 nm synthesized by sol gel and 47 nm prepared by precipitation. ▶ The nano-structured ZnO particles were characterized by XRD, FESEM, EDXS and TEM. ▶ The nano-ZnO shows higher photocatalytic activity than commercial ZnO for phenol degradation. ▶ The operational parameters significantly influence the degradation of phenol. Zinc oxide nanoparticles were synthesized by precipitation and modified sol gel methods. The influence of calcination temperature on morphology and crystallite size of ZnO was studied by varying temperature from 400 to 700 °C. The nano-structured ZnO particles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDXS) and tranmission electron microscopy (TEM). The photo catalytic activity of as-prepared ZnO was evaluated by degradation of phenol under UV laser irradiation. The Photocatalytic degradation (PCD) efficiency of ZnO was found to decrease with the increase in calcination temperature due to agglomeration of particles and the increase in particle size. In addition to the effect of calcination temperature, the influence of various other parameters such as photocatalyst concentration, initial pH and the initial phenol concentration was also investigated to achieve the maximum PCD of phenol. The operational parameters show the expected influence regarding the efficiency of the photocatalytic degradation process. The results follow the pseudo-first order rate kinetics.