MOF-derived Co3O4-C@FeOOH as an efficient catalyst for catalytic ozonation of norfloxacin

Metal-organic frameworks (MOFs) ZIF-67-derived Co3O4-C@FeOOH composite was prepared, characterized and used as an efficinet catalyst for ozonation of norfloxacin (NOF). Results showed that ZIF-67-derived Co3O4-C composite maintained the polyhedral structure of ZIF-67. After modification, abundant amorphous FeOOH nanowire attached on the surface of Co3O4-C composite, resulting in Co3O4-C@FeOOH interwoven polyhedrons. Furthermore, the specific surface area of the formed composite was about 2.5 times that of Co3O4-C composite, which might provide more active sites for catalytic reaction. Compared with single ozonation system, the catalytic ozonation process (Co3O4-C@FeOOH/O-3) had better performance in NOF mineralization under the same operating conditions. Moreover, in the presence of Co3O4-C@FeOOH, faster O-3 decomposition and higher center dot OH concentration were observed, which could explain the significant enhancement of TOC removal. The coexistence of Fe and Co in various valence states in catalyst might improve the conversion of Co(III)/Co(II) and Fe(III)/Fe(II), which would increase the catalytic activity in catalytic ozonation process. Besides, several main intermediate products were detected and possible NOF degradation pathway was proposed.

Automated summary

The ZIF-67-derived Co3O4-C@FeOOH composite showed efficient catalytic activity in the ozonation of norfloxacin (NOF), providing more active sites for the reaction and achieving better performance in mineralization. The presence of Fe and Co in various valence states in the catalyst improved the conversion of Co(III)/Co(II) and Fe(III)/Fe(II), enhancing the catalytic activity. Multiple intermediate products were detected, and a possible degradation pathway for NOF was proposed.