ZnO nanoparticles, stacked on the bottom of a glass dish, were used as a catalyst for the photodegradation of aqueous 2-chlorophenol (2-CP) contaminant. Solutions of 2-CP at different concentrations and pH values were passed over the ZnO film under simulated solar light.The effect of the light intensity on the contaminant photodegradation rate was investigated. The photodegradation efficiency was evaluated based on the percentage degradation, turnover number, turnover frequency, and quantum yield. The reaction efficiency parameters showed no significant variation when changing the pH across moderate values (neutral, slightly basic, and slightly acidic). Complete mineralization of the contaminant to CO2, H2O, and other minerals was confirmed by various analytical methods including high-performance liquid chromatography, ultraviolet–visible (UV–Vis) spectroscopy, and total organic carbon measurements.The continuous flow method applied in this work showed promising results in terms of safe removal of 2-CP from water at laboratory scale. More study of this method is needed to enable its use at larger, pilot plant scale. © 2020, The Minerals, Metals & Materials Society.