In this work, zinc oxide (ZnO) nanoparticles were prepared by the solid-solid reaction technique. The photocatalytic efficiency, using a ZnO nanoparticle as a catalyst, has been shown by investigating the degradation rate of an extreme quantity of potassium permanganate (KMnO4) in wastewater. The KMnO4 dye reveals a degradation rate of 47% by the irradiation of UV compared to less than 5% for methylene blue using the same experiment conditions by ZnO nanoparticles as a catalyst. Also, various kinetics models such as the pseudo-first-order, the pseudo-second-order, and the intra-particle diffusion models are applied to investigate the photocatalytic process. Moreover, Boyd and Elovic models were applied to study in detail the mechanisms of the photocatalytic degradation process.