The present work is focused on the adsorption and photodegradation of carbendazim on the surface of ZnO nano particles. The reaction carried out in a Pyrex photoreactor equipped with a Krypton lamp. The effect of initial concentration under UV light irradiation is examined. The kinetic of the removal is explained in terms of the Langmuir–Hinshelwood model. The values of the adsorption equilibrium constant, K, and the kinetic rate constant of surface reaction, kc, are calculated. The results show that more than 90 percent of the substrate is removed after 90 minutes. To obtain the adsorption properties, the ZnO surface is modeled as two clusters, Zn21O36H30 and Zn12O18H12. In the theoretical study, geometry optimization and vibrational analysis for adsorption on cluster is calculated by density functional theory method at B3LYP/lanl2DZ level. The results show that the adsorption energies depend on the surface model and organic compound prefers to be adsorbed molecularly on the ZnO (0001) surface.
