Optimization and statistical modelling of electrochemical removal of oxytetracycline from aqueous solutions

Abstract In this study, the removal efficiency of OTC antibiotics from pharmaceutical wastewater streams was evaluated by electrooxidation (EO) and electrocatalytic oxidation (ECO) methods under different parameters. In catalytic studies, activated carbon supported TiO 2 /AC catalyst was successfully synthesized for OTC removal by sol–gel method. These catalysts were characterized by various analytical methods such as XRD, TEM, SEM, DSC and BET. The intermediate products formed in the electrochemical degradation of the OTC antibiotic were determined by high-resolution mass spectrometry analysis. UV/Vis spectrophotometry and cyclic voltammetry analyses were also performed to determine the concentration and electrochemical properties of the electroactive components present in the solution. In the experimental set design, the optimum conditions for EO studies were determined as 15 V voltage, 0.5 g/L salt amount, 7 pH value, 36 mg/L initial concentration and 45 min contact time, while for ECO experiments, these conditions were 10 V voltage, 0.25 g/L catalyst amount, 7 pH value, 30 mg/L initial concentration and 30 min contact time. According to the results of EO and ECO experiments, 79% and 86% removal efficiency was achieved on the simulated OTC effluent, respectively. The results show that TiO 2 /AC catalysts contribute to more efficient degradation of OTC molecules by accelerating electrochemical reactions and offer a potential solution for the removal of such pollutants. It was also found that an experimental design based on the CCD-RSM optimization model could be an important consideration for better understanding, optimizing and increasing the efficiency of the catalytic process. Graphic abstract