Electrochemical degradation of tetracycline antibiotic with boron-doped diamond electrodes and effect of parameters on removal of reaction intermediates

Electrochemical degradation of tetracycline antibiotic and the effect of process parameters on removal of reaction intermediates was investigated with boron-doped diamond electrodes. The parameters of tetracycline concentration (200-1,000 mg/L), NaCl concentration (0-8 g/L), current density (4-20 mA/cm(2)) and reaction temperature (25 degrees C-45 degrees C) were analyzed on tetracycline removal, chemical oxygen demand (COD) removal, intermediates removal, and energy consumption. The optimum values of the parameters were obtained by response surface methodology such as tetracycline concentration, 618 mg/L; NaCl concentration, 3.6 g/L; current density, 13.4 mA/cm(2), and reaction temperature, 36 degrees C. Under optimum conditions, the removal efficiencies of tetracycline, COD, and intermediates were obtained as 98.7%, 98.2%, and 92.5%, respectively, with 78 kWh/kg CODr energy consumption. Electrochemical degradation rate of tetracycline antibiotic was higher in 10 min while intermediates started to produce after 2 min. The amount of the degradation products reached maximum in 15 min which then further oxidized and removed in high extent (>= 97%) depending on reaction conditions. The removal of intermediates occurred at a much lower rate than tetracycline degradation.