Amoxicillin degradation in the heat, light, or heterogeneous catalyst activated persulfate systems: Comparison of kinetics, mechanisms and toxicities

Various activated persulfate (PS) technologies have been investigated and implemented to eliminate antibiotic contaminants from water. The investigation and evaluation of different activation systems are essential for the application of PS techniques. The degradation of amoxicillin (AMX) by heat, light, or heterogeneous catalyst of Fe-AC composite activated PS was investigated, and the kinetics, mechanisms and toxicities were compared in this work. The apparent activation energy of the Fe-AC system was lower than that of the heat system. Hydroxyl and sulfate radicals were demonstrated by electron paramagnetic resonance (EPR) spectroscopy and quenching tests. There were 22, 21 and 13 types of degradation intermediates detected in heat, light and Fe-AC system, respectively. Six pathways of AMX degradation were proposed and compared in the three activated PS systems. The toxicity prediction of degradation intermediates under different treatment processes was estimated by ecological structure-activity relationship model and toxicity estimation software tool. The genotoxicity of the AMX degradation solution was tested by Acinetobacter baylyi ADP1_recA, which indicated that the AMX solution after treatment in the Fe-AC system had almost no genotoxicity. The Fe-AC/PS system shows apparent advantages over the heat or light activated PS system in most cases, demonstrating that the Fe-AC/PS system is suitable for AMX-contaminated remediation in aqueous solution.