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Concerns about environmental pollution from antibiotics such as amoxicillin have received increasing attention. These compounds should be eliminated from discharged effluents to avoid their possible negative effects on humans and animals, as well as on the environment. Recently, advanced oxidation techniques have been used to remove antibiotics. This work aims to study the removal of amoxicillin using a photocatalysis/ozonation process for treating pharmaceutical wastewater loaded with this type of refractory pollutants. The removal process was carried out using different pH values (3-11), catalyst dosages (250-750 mg/L), and reaction times (30-90 min), at an ozonation rate of 200 mg/h. Statistical analysis indicated that a quadratic model was suitable for modeling amoxicillin degradation by the photocatalytic process and that all studied parameters had statistically significant critical levels. Under optimum conditions (pH 11, a catalyst dose of 500 mg/L, and a reaction time of 90 min), the amoxicillin degradation efficiency of the photocatalytic process was 78.7%. The results of the photocatalysis/ozonation process indicated that after 90 min of ozone injection, an amoxicillin degradation efficiency of 98.7% was obtained. Therefore, it was concluded that the combined ozonation process and photocatalytic process could be used to remove amoxicillin effectively.

In this study, the photocatalytic degradation of 2,4,6-trichlorophenol (2,4,6-TCP) was evaluated under UV radiation by Fe-doped titanium dioxide (Fe-doped TiO 2 ) nanoparticles (NPs) which were synthesized by a sol-gel method. Diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were applied to identify the synthesized nanoparticles. According to the SEM image, the synthesized nanoparticles had fine and irregular shapes with relatively smooth surfaces, as well as XRD spectrum showed that the crystalline size of Fe-doped TiO 2 NPs was 10.42 nm, furthermore, according to the DRS analysis, the bandgap energy of Fe-doped TiO 2 NPs was determined about 2.9 eV. The effects of operating parameters, including initial 2,4,6-TCP concentration, pH, contact time and Fe-doped TiO 2 NPs dosage on 2,4,6-TCP degradation were studied and optimized based on the response surface methodology with Box-Behnken method. The analysis of 2,4,6-TCP degradation showed that under optimum conditions, the removal efficiency reached 95.9% which is consistent with the model prediction. The optimum degradation conditions were as follows: pH, 3.29; initial 2,4,6-TCP concentration, 50.5 mg L -1 ; Fe-doped TiO 2 NPs dosage, 0.59 g L -1 ; and contact time, 55.7 min. The present results showed that Fe-doped TiO 2 NPs have great potential for removing 2,4,6-TCP from aqueous solutions.

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