fa تخصصي Special مقاله اصیل Original Article <div style="text-align: justify;">Background: The presence of pharmaceutical substances and their residual in water resources is an important environmental concern. Azithromycin, an antibiotic that is used for the treatment of infectious diseases, is a pollutant agent in the wastewater. The aim of this study was to investigate azithromycin degradation in aqueous solution through ultrasonic process in the presence of zinc oxide nanoparticles as catalysts.<br> Methods: Sonocatalytic experiments were performed at variable conditions including pH (3-8), temperature (20-60&deg;C), time (3-21 minutes), catalyst dosage (0.25-2 g/L), hydrogen peroxide concentration (15-100 mg/L) and initial azithromycin concentration (10-100 mg/L).<br> Results: The optimum values for pH (3), temperature (40&deg;C), time (15 minutes), catalyst dosage (1 g/L), H2O2 concentration (50 mg/L) and initial azithromycin concentration (20 mg/L) were determined. The highest degradation efficiency of 98.4% was achieved after 15 minutes of ultrasonic irradiation under optimum condition.<br> Conclusion: According to the results, ultrasonic irradiation is able to degrade azithromycin. In addition, ZnO and hydroxyl radical can successfully accelerate the reaction process in the shortest possible time.</div> Azithromycin, Catalysis, Wastewater, Ultrasonics 85 92 http://ehemj.com/browse.php?a_code=A-10-1-115&slc_lang=fa&sid=1 Atiyeh Yazdani 10031947532846008376 10031947532846008376 No Department of Environmental Sciences, Faculty of Natural Resources and Environment, University of Birjand, Birjand, Iran Mohammad Hossein Sayadi Mh_sayadi@birjand.ac.ir 10031947532846008377 10031947532846008377 Yes Department ofvironmental Sciences, Faculty of Natural Resources and Environment, University of Birjand, Birjand, Iran