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

Abstract

Tetracycline is a well-known emerging contaminant which affects water environment. In this study, an electro/peroxydisulfate system catalyzed with Fe 2+ loaded on granular activated carbon (EC/Fe-GAC/PS) was used to treat tetracycline hydrochloride (TCH). Experimental results indicated that the removal efficiency of TCH was 86.12% by the EC/Fe-GAC/PS system. When TCH initial concentration was less than 20 mg/L, the removal efficiency of TCH was similar. The removal efficiency of TCH reached highest value when initial pH was 3, Fe-GAC concentration was 0.5 g/L and plate spacing was 9 cm, respectively. When the concentrations of PS and Na 2 SO 4 reached 3.0 mmol/L and 25 mmol/L, respectively, the removal rate of TCH was the highest. When the current density increased to 20 mA/cm 2 , the degradation efficiency of TCH began to decline. When the plate spacing is 9cm, the residual amount of TCH is the lowest. In a certain range, separately increasing of PS concentration, Na 2 SO 4 concentration, and current density would enhance the degradation efficiency of TCH. The free radical experiments showed that SO 4•played a leading role in acid conditions. According to data analysis, the reaction kinetic model of EC/Fe-GAC/PS system fitted first-order reaction kinetic model. The order of factors affected reaction efficiency was: plate spacing>current density>PS concentration>Fe-GAC concentration>Na 2 SO 4 concentration in the EC/Fe-GAC/PS system. This study showed that the EC/Fe-GAC/PS process was an efficient, environmental friendly and feasible way to degrade the tetracycline antibiotics in water.