Rapid degradation of tetracycline in aqueous solution by Fe/Cu catalysis enhanced by H₂O₂ activation

Tetracycline (TC) is widely detected in the environment because of its abuse and persistence. There is an urgent need to efficiently treat TC due to its potential threat to the ecosystem and human health. In this study, microscale Fe/Cu bimetallic particles' (mFe/Cu) catalysis enhanced by H₂O₂ was proposed to remove TC in an aqueous solution. Based on the pre-experiment, the effect of theoretical Cu mass loading (TML_Cu) and some key operating parameters on the TC removal efficiency were investigated thoroughly. The degradation rates of TC by mFe/Cu with different TML_Cu followed the pseudo-first-order kinetics model, and the optimal TML_Cu (0.34 g Cu/g Fe) was obtained. The optimal operating parameters of mFe/Cu dosage, concentration of H₂O₂, initial concentration of TC, stirring speed and operating temperature were 5 g/L, 50 mM, 50 ppm, 400 r/min, and 55°C, respectively. Compared with the control system, the system of mFe/Cu catalysis enhanced by H₂O₂ (mFe/Cu-H₂O₂) presented excellent performance due to its synergistic effect. Also, the fresh and reacted mFe/Cu was characterized by scanning electron microscope, which showed the surface of mFe/Cu was rougher after reaction, indicating mFe/Cu participated in the degradation reaction. Besides, with the presence of inorganic anions, the degradation of TC in mFe/Cu-H₂O₂ system did not change much. And mFe/Cu presented good stability and recyclability after 10 repeated tests. Therefore, mFe/Cu-H₂O₂ system had a great potential for cost-effective removal of antibiotics in wastewater.