Non-radical activation of persulfate by CuO catalyst for degradation of antibiotics

Abstract

Advanced oxidation process (AOP) based on persulfate (PS) activation has attracted numerous attentions for antibiotic elimination due to the high stability and low cost of PS. In this work, a non-radical activation of PS by CuO catalyst was developed to efficiently degradation of antibiotics. Employing moxifloxacin (MOX) as model pollutant, the CuO/PS system showed excellent degradation rate for 100 mg L−1 MOX that is 13.2 and 7.7 times higher for than the single CuO and PS, and meanwhile the performance is also much better than the typical AOP heterogeneous catalyst Fe2O3 in both neutral and acidic solutions. The optimization experiments indicate the optimal PS concentration is 2.5 mM, and the CuO/PS system can work in a wide pH range for different MOX concentrations. Furthermore, the CuO catalyst has high structural stability and catalytic durability, and the CuO/PS system has good practicality that can degrade a variety of antibiotics and be used in different aquatic environments. Based on various characterizations, a non-radical PS activation route on the CuO surface was proposed. Finally, toxicity assessment of the detected intermediates implies that the toxicity and the potential risk to the environment were effectively decreased. This work testifies PS can be efficiently activated by CuO through a non-radical pathway and presents superior performance for antibiotic elimination.