Efficiency of Photocatalytic Ozone Process Combined with Zinc Oxide in Removal of Amoxicillin from Hospital Wastewater

Background and purpose: One of the main problems of pollution of aquatic environments is hardly biodegradable chemicals with high toxicity such as antibiotics. If they are not removed from the wastewater, particularly the hospital wastewater, many health and environmental hazards are created. Therefore, appropriate management and treatment of this type of wastewater is highly necessary. This research aimed at investigating the efficiency of advanced oxidation process by ozone photocatalytic method combined with zinc oxide in removal of amoxicillin from wastewater. Materials and methods: The present study was conducted on laboratory scale in a pre-designed reactor. The effects of ozone concentration (5-10 mg/min), catalyst concentration (0.25-1.5mg/l), amoxicillin concentration (10-100 mg/l), and pH (3-11) were investigated on the process efficiency by HPLC. Thirty specimens were studied using central composite design method and the information was evaluated by surface response method using Design Expert7. Data analysis was done applying ANOVA and regression analysis. Results: The removal efficiency of amoxicillin was 93% under optimal conditions (ozone dose: 3 mg/min, pH 11, catalyst dose: 0.875 mg/l, and amoxicillin concentration: 55mg/l). ANOVA and regression analysis showed that the fitted model properly matched with laboratory results. Conclusion: This study showed that the ozone photocatalytic process along with zinc oxide could be applied as a suitable and effective method in treatment of antibiotics in aqueous environments.