عنوان مقاله [English]
In this study, the removal and degradation of organic pollutants from real oil refinery effluent was investigated using a synthesized TiO2/Ag photocatalyst fixed on lightweight concrete plates. Petroleum compounds are the set of hydrocarbons some of which are stable, long-term decomposing, poisonous and even carcinogen for human. One of the attractive wastewater treatment techniques is photocatalytic purification and this process has the potential to mineralize all organic and inorganic compounds found in petroleum impregnated processes and convert them into biodegradable and biodegradable compounds. Characterization of synthetic photocatalysts was done using X-ray diffraction (XRD) Fourier transform infrared spectroscopy (FT-IR) techniques, scanning electron microscopy (SEM) with EDX analysis and nitrogen adsorption and desorption (BET). The photocatalytic pilot consisted of three 20×20×5cm lightweight concrete plates that coated the nanoparticles on the concrete surface and were powered by 36-watt UVA lamps. SEM experiment results showed relatively uniform TiO2/Ag coating on lightweight concrete surface. The synthesized photocatalyst XRD pattern showed the successful synthesis of Ag crystals in the nanocomposite structure. BET results showed that when TiO2/Ag is synthesized, the cavities become mesoporous. Investigation of the effect of pH on the system efficiency in the range of 3 to 12 showed that at pH 4.5 the removal efficiency reached its highest level. The effect of mass loading of TiO2/Ag nanoparticles on the concrete plates showed that the highest removal efficiency in mass loading was 15 gr/m2. To study the rate of COD removal under sun light, the reactor was transferred to the yard in Kharazmi University in Tehran. To obtain results, the experiment was performed three times foe both states of using TiO2 and TiO2/Ag under optimum condition. The rate of COD removal under sunlight for 8 hours and the use of UV-A lamps for TiO2/Ag photocatalysts were 51.8% and 76.3%, respectively. The results showed that the synthetic photocatalyst is capable of treatment of real wastewater by using UV rays.