Electrochemical Removal of Cephalosporin Antibiotic—Cefuroxime Axetil from Aquatic Media Using Boron-Doped Diamond Electrodes: Process Optimization, Degradation Studies and Transformation Products Characterization

Growing environmental concern over pharmaceutical contaminants in water, combined with the limited effectiveness of conventional treatment methods in removing persistent antibiotics, creates a need for advanced remediation technologies. This study investigates the degradation of the cephalosporin antibiotic cefuroxime axetil using an electrochemical advanced oxidation process with a boron-doped diamond (BDD) anode. Experiments were conducted under varying pH levels and in natural water matrices, specifically river and lake water, to evaluate the process efficiency under realistic conditions. Significant differences were observed between matrices, with the best result obtained in river water, enabling complete degradation of cefuroxime axetil within 30 min. To clarify the factors influencing process efficiency, additional experiments examined the effects of dissolved organic matter (DOM) and chlorides. Cefuroxime axetil proved highly susceptible to electrooxidation, generally following pseudo-first-order kinetics, and chloride significantly accelerated its degradation. Using high-resolution mass spectrometry, ten transformation products were identified, including six not previously reported in the literature, representing a key novelty of this work. Their potential aquatic toxicity was subsequently evaluated in silico using fish and algae models. Finally, energy consumption analysis was conducted to evaluate the impact of various factors on the process's economic efficiency.