In-situ green synthesis of fibrous leaf-like bimetallic ZIF/PAN membranes for high-performance norfloxacin degradation

Metal-organic framework (MOF)-derived catalysts have received growing attention as promising materials for wastewater decontamination . However, the practical use of these catalysts still encounters many challenges, such as poor separation from the reaction mixture, sub-ideal catalytic performance of monometallic MOFs, and large consumption of organic solvents in the preparation process. To address these issues, we adopted a “seed-growth epitaxial” strategy, substituting MeOH with the green solvent H 2 O to synthesize an environmentally friendly leaf-like vine-weaved fiber membrane, composed of two-dimensional bimetallic zeolitic imidazolate framework (ZnCo-ZIF) and polyacrylonitrile (PAN), which was utilized to activate peroxymonosulfate (PMS) for the degradation of norfloxacin (NOR). The ZnCo-ZIF/PAN fiber membrane possesses a substantial specific surface area , facilitating the uniform and efficient exposure of bimetallic active sites. The results showed that ZnCo-ZIF/PAN was highly efficient in PMS activation, achieving a 93 % NOR removal within 120 min. The removal efficiency of NOR increased in accordance with doped Co. The catalyst demonstrated relatively high activity in the pH range of 3.0∼7.0. The radicals quenching experiments proved that SO 4 · − and ·OH were the crucial reactive oxygen species (ROS), which confirmed by electron paramagnetic resonance spectroscopy (EPR). The degradation pathways were proposed according to the intermediates identified by high-performance liquid chromatography-coupled mass spectrometry , including dehydrogenation , defluorination , hydroxylation , piperazinyl ring transformation, and quinolone group transformation. Importantly, the flexible ZnCo-ZIF/PAN composite nanofiber membrane can be separated 100 % from treated wastewater to solve the recycling and reuse problem of nanopowders . This study provides a new perspective for the design of bimetallic ZIF composite fibers with excellent catalytic properties and offers new ideas for their application in practical production.