Efficacy and mechanism of peracetic acid activation with CuFeS2 to degrade tetracycline: Synergy of copper and iron species

Tetracycline, representing as the typical antibiotics, is widely utilized and commonly detected at high concentrations in aquatic environments. Advanced oxidation technologies leveraging the high reactivity of radicals generated by activated peracetic acid via iron-based heterogeneous activators exhibit excellent effectiveness for tetracycline removal, yet this process is hampered by the slow reduction of >Fe(III) to >Fe(II). Regarding the redox reversibility of CuFeS 2 and the electron-donating properties of sulfur components in accelerating the reduction of >Fe(III) to >Fe(II), the combination of CuFeS 2 and peracetic acid (simplified as the CuFeS 2 /PAA system) is developed. At a low CuFeS 2 dosage of 0.03 g L −1 , tetracycline was degraded with a degradation rate of 0.167 min −1 under neutral conditions, which was more effective than CuS and FeS 2 . The efficacy is consistent the electron-transferring ability of CuFeS 2 , CuS and FeS 2 . CuFeS 2 exhibits enhanced catalytic activity due to its unique redox properties, in which >Fe(II) sites facilitate PAA activation, while >Cu(I) is essential for >Fe(III) reduction, creating a synergistic interaction that accelerates >Fe(III) reduction to >Fe(II). As the main radical generated, CH 3 C( O )OO• plays a key role in tetracycline degradation. It is also indicated that different water quality parameters slightly impact tetracycline degradation, highlighting the system's robust practical application potential. By facilitating the rapid reduction of >Fe(III) to >Fe(II), the CuFeS 2 /PAA system can achieve effective tetracycline degradation. This study is expected to provide a feasible method for the treatment of the water and wastewater containing antibiotics.