Tuning the heterostructure improves the catalytic activity of recyclable nanozymes for efficient absorption and degradation of norfloxacin-contaminated water

Effective removal of antibiotic residues from water is crucial for maintaining balance and cleanliness in the ecological environment. To achieve this, we conducted a study on the development of a highly efficient catalyst from the in-situ growth of Fe3O4 nanoparticles on nitrogen-doped hollow porous carbon spheres (Fe3O4@NHollCS). We controlled the in-situ growth time to optimize its performance. Material characterization and theoretical calculations revealed that the improved catalytic performance of Fe3O4@N-HollCS is due to electron transfer from the graphitic-N in N-HollCS to the catalytic interface of Fe3O4 nanoparticles. Fe3O4@N-HollCS, with an ordered mesoporous structure and high specific surface area, had remarkable adsorption capacity for NOR antibiotics, with an enrichment efficiency exceeding 60% within 10 min. Moreover, the Fe3O4@N-HollCS degraded more than 90% of fluoroquinolone antibiotics, especially norfloxacin (NOR), which was eliminated within 60 min. The Fe3O4@N-HollCS also exhibited stable catalytic recycling ability within 10 magnetic separations. Fukui function predicted the sensitive sites of NOR, and we proposed potential degradation pathways. Ecological structure activity relationship model evaluation showed that the intermediate produced by Fe3O4@NHollCS degradation of NOR has low levels of ecotoxicity. Overall, Fe3O4@N-HollCS catalysts have great potential for antibiotic wastewater treatment.