Electrochemical degradation of ciprofloxacin through a DoE-driven optimization in a filter-press type reactor under batch recirculation mode

Abstract

In this work, the electrochemical degradation of ciprofloxacin (CIP) was studied in a filter-press-type reactor without division in a batch recirculation manner. For this purpose, two boron-doped diamond (BDD) electrodes (as cathode and anode) were employed. Also, the optimal operating conditions were found by response surface methodology (RSM) following a central composite face-centered design with three factors, namely current intensity (i), initial pH (pH0), and initial concentration ([C]0) with two responses, namely remotion efficiency (η) and operating cost. Optimal operating conditions were i = 3 A, pH0 = 8.49, and [C]0 = 33.26 mg L−1 within an electrolysis time of 5 h, leading to a maximum removal efficiency of 93.49% with a minimum operating cost of $0.013 USD L−1. Also, a TOC analysis shows an 80% of mineralization extent with an energy consumption of 5.11 kWh g−1 TOC. Furthermore, the CIP degradation progress was followed by mass spectrometry (LC/MS) and a degradation pathway is proposed. HIGHLIGHTS Ciprofloxacin has been removed efficiently in a flow-by reactor equipped with two BDD electrodes.; Optimal operating conditions were pH0 = 8.49, i = 3 A, and [C]0 = 33.26 mg L−1.; Mineralization efficiency and extent of electrochemical combustion at optimal operating conditions were 80% and 0.85.; Three pathway reactions for the electrochemical degradation of CIP were described.;

Keywords

• bdd electrodes
• central composite face-centered design
• ciprofloxacin
• degradation pathway
• doe-driven optimization