Core-shell magnetic Fe3O4/CNC@MOF composites with peroxidase-like activity for colorimetric detection of phenol

Rapid and accurate detection of phenolic wastewater from industries has created global concern. Herein, core-shell magnetic cellulose nanocrystal supported MOF (Fe3O4/CNC@ZIF-8) with robust peroxidase-like activity was synthesized with tannic acid as modifier and bridge. The peroxidase-mimic catalytic activity of as-prepared Fe3O4/CNC@ZIF-8 was further investigated using o-phenylenediamine (OPD) as peroxidase substrates in the presence of H2O2. Moreover, the experimental conditions were optimized and the kinetic analysis results showed that Fe3O4/CNC@ZIF-8 had higher affinity towards both the substrate OPD and H2O2 than horseradish peroxidase (HRP). Finally, a phenol colorimetric assay with a linear range of 2-200 mu M and a detection limit of 0.316 mu M was constructed. The catalytic mechanism of Fe3O4/CNC@ZIF-8 with phenol was further investigated by fluorescence test and the generated center dot OH was proved to act a crucial role to produce quinoid radicals. Additionally, the synthesized magnetic material had excellent stability and recyclability and ease to separation. These results suggest that the Fe3O4/CNC@ZIF-8 may be one of the promising candidates as peroxidase mimic for colorimetric detection of phenol.

Automated summary

This study synthesized Fe3O4/CNC@ZIF-8 with peroxidase-like activity using tannic acid as modifier, showing higher affinity towards OPD and H2O2. A phenol colorimetric assay was developed with a linear range of 2-200 μM and a detection limit of 0.316 μM, indicating Fe3O4/CNC@ZIF-8 as a promising candidate for colorimetric detection of phenol.