Construction of metal-organic framework@cellulose nanofiber aerogel based on directional freezing for degradation of organic pollutants

Metal-organic frameworks (MOFs) can efficiently degrade organic pollutants through advanced oxidation process (AOP). However, the retrieval of MOFs from the solution poses a considerable challenge due to their powdery nature, thereby restricting their potential applications. Herein, a composite aerogel loaded with MOFs on cellulose nanofiber aerogel was prepared by directional freezing technology, which has orderly pore arrangement and excellent degradation performance. Directional freezing Co-MIL-53(Fe)@CNF has regular arranged pore structure and metal catalytic sites, efficiently activating peroxymonosulfate (PMS) and promoting the degradation of tetracycline hydrochloride (TC). The free radical quenching experiment and the electron paramagnetic resonance (EPR) experiment concurrently suggest that sulfate radicals and hydroxyl radicals, as prominent free radical species, play crucial roles in the degradation of TC. The pH level of the solution exhibits no discernible influence on the degradation process, indicating that the aerogel has good pH tolerance. This work provides a new strategy for developing an effective catalyst to activate PMS to eliminate antibiotics.