Green synthesis of Co-Ce ZIF derivatives for enhanced O3/PMS degradation of levofloxacin

Abstract

Antibiotics that permeate aquatic environments present significant risks to both ecosystems and human health. In this study, we employed the techniques of room temperature aqueous solution precipitation to fabricate ZIF-67 derivatives, and established a Co3O4/CeO2/O3/PMS (Co-Ce/OP) system. Furthermore, a 10 mg/L Levofloxacin (LEF) solution could reach rapid degradation (97.2%) and effective mineralization (40.4%) under specific conditions. Subsequent investigations identified the primary active substances, intermediates, and reaction mechanism in the Co-Ce/OP system. Evidence from Electron Paramagnetic Resonance (EPR) and quenching experiments indicates that SO4·-, OH·, O2·- and 1O2 contribute to the degradation process. Applying High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), we discovered that the principal degradation mechanisms for LEF encompass the cleavage and subsequent loss of the piperazine, quinolone, and morpholine rings, in addition to decarboxylation and defluorination reactions. Besides, we studied the acute toxicity, bioconcentration factor, developmental toxicity, and mutagenicity of LEF and its intermediate products. Our findings reveal a notable reduction in the toxicity of the intermediate products relative to LEF. Later experiment demonstrates that the degradation rate of LEF sustains above 90% after five cycles of reactions, indicative that the catalyst has excellent recyclability and stability. Furthermore, this study employed experiments across four different natural water matrices, demonstrating the system's considerable potential for effective application within authentic aquatic settings.