Photocatalytic Degradation of Amoxicillin and Levofloxacin from Aqueous Solutions Using Ag/ZnO

Water pollution caused by antibiotics is a serious problem worldwide and particularly in Iran. Therefore, it is necessary to employ an effective method to eliminate antibiotic pollutions. In this research, the degradation of amoxicillin and levofloxacin antibiotics in aqueous solutions was studied using Ag/ZnO photocatalysis under the A-type ultraviolet irradiation (UV-A 365 nm). Having conducted the experiments, the Ag/ZnO composite was first synthesized by dispersing zinc oxide in silver nitrate. Afterward, the structure and properties of Ag/ZnO nanoparticles were characterized by XRD, FESEM, and EDX techniques. In the meant time, the concentration of antibiotics and total organic carbon (TOC) were determined by UV-VIS spectrophotometer and TOC analyzers, respectively. The process efficiency has also been investigated under the influence of the following treatments: the effects of solution pH (3-11), initial concentration of amoxicillin and levofloxacin (5-30 mg/l), catalyst dosage (0.075-0.3 g/l), and reaction time (15-120 min). Based on the results, the highest efficiency in amoxicillin removal was determined (93.7%) in optimal conditions of Ag/ZnO at 0.15 g/l, pH 5, amoxicillin concentration 5 mg/l, and 120 min contact time. while the optimum condition for levofloxacin removal was achieved at 0.15 g/l catalyst dosage, pH 9.0, 120 min reaction time, and levofloxacin concentration of 5 mg/l. Under these conditions, the levofloxacin and TOC removal efficiency was 88.4% and 84.56%, respectively. The results showed that Ag/ZnO nanoparticles in the presence of the UV-A can efficiently remove amoxicillin and levofloxacin from aqueous solutions.