Degradation Of Tetracycline Antibiotic in Water by an Electro/Peroxydisulfate System Catalyzed with Fe2+ and Cu2+ Loaded on Activated Carbon

Tetracycline antibiotics are a common type of antibiotics in life. In this research, Fe²⁺ and Cu²⁺ was used to modify granular activated carbon, and peroxydisulfate was activated under the synergistic action of electrochemistry (EC/Fe-Cu-GAC/PS). The effects of the initial concentration of tetracycline hydrochloride (TCH), initial pH, current density, and plate spacing on the degradation of TCH were investigated. Experimental results indicated that the removal efficiency of TCH was 87.27% by the EC/Fe-Cu-GAC/PS system. The removal rate of TCH decreased with the increase of initial concentration of TCH. The TCH removal rate is maintained at a high level when pH values range from 3 to 7. Increasing the amount of catalyst and persulfate in a certain range, as well as the magnitude of current density and plate spacing are helpful for TCH removal. When the initial TCH concentration is 20 mg/L, the initial pH value is 5.0, the amount of Fe-Cu-GAC is 2.0 g, the PS concentration is 2 mmol/L, the electrolyte concentration is 25 mmol/L, the current density is 15 mA/cm², and the plate spacing is 9 cm, the TCH removal effect is the most effective. The free-radical experiment showed that sulfate radicals (SO₄^•−) played a dominant role under acidic conditions. According to the data analysis, the kinetic model of the EC/Fe-Cu-GAC/PS system was consistent with the first-order reaction kinetics. According to the reaction dynamics, we get the rating of influencing factors that influence the effect of TCH removal. The EC/Fe-Cu-GAC/PS system can effectively degrade tetracycline antibiotics in water.