Flumequine ( <scp>FLQ</scp> ) removal from aqueous solution by electrochemical methods and optimization with central composite design under response surface methodology ( <scp>CCD</scp> ‐ <scp>RSM</scp> ) model

Abstract The removal performance of pharmaceutical waste Flumequine (FLQ) antibiotic was examined in different parameters by electrochemical oxidation (EO) and electrocatalytic (ECO) methods. Experiments were carried out using both graphite electrodes and particle electrodes. In catalytic studies, activated carbon supported TiO 2 /AC catalyst synthesized by the sol–gel method was used. SEM, TEM, XRD and DSC analyses were performed to characterize the structure and morphology of the synthesized catalyst. Intermediates formed as a result of the degradation of the FLQ antibiotic were determined by HRMS analysis. UV–Vis spectrophotometry and cyclic voltammetry analyses were performed to determine the concentration and electrochemical properties of the electroactive components in the solution. The CCD‐RSM optimization model was applied in designing the experiments to optimize the parameters. The amount of catalyst, concentration, pH, amount of salt, voltage effect and contact time constitute the main parameters of this design. A quadratic model was used for variable predictions. In the experimental set design, the optimum conditions for electrooxidation (EO) studies were determined as 15 V voltage, 0.5 g/L salt amount, 5.4 pH value, 35 mg/L initial concentration and 45 minutes contact time, while for electrocatalytic (ECO) experiments these conditions were 7 V. voltage, 0.25 g/L catalyst amount, 5 pH value, 40 mg/L initial concentration and 60 minutes contact time. As a result of the EO and ECO experiments, 81% and 98% removal efficiencies were obtained, respectively on the simulated FLQ waste.