Photocatalytic destruction of potassium hydrogen phthalate using TiO2 and sunlight: application for the treatment of industrial wastewater

The applicability of the photocatalytic detoxification for the treatment of Ras Lanuf Oil Co. (RASCO) wastewater was studied using potassium hydrogen phthalate (KHP) as a model compound. The conditions of the photocatalytic degradation process of KHP were optimised. Its disappearance in a titanium dioxide suspension, irradiated by sunlight, was followed by chemical oxygen demand (COD). The optimum catalyst concentration was found at 3 g/l of Degussa P25 and 10 g/l of Sachtleben Hombikat UV 100. The optimum degradation rate was obtained at pH 5.0 for both types of catalyst. The disappearance of KHP in the dark, using Sachtleben Hombikat UV 100, was due to the adsorption of the pollutant on the catalyst surface. The photonic efficiency was decreased at low light intensities (0.311–2.29 μmol photon s−1 l−1) with I−0.243 and at higher light intensities (2.29–2.919 μmol photon s−1 l−1) with I−0.94. The complete degradation of organic pollutants in RASCO wastewater was achieved after 5 h of irradiation using the optimised reaction conditions obtained for KHP.