Fabrication of hollow covalent-organic framework microspheres via emulsion-interfacial strategy to enhance laccase immobilization for tetracycline degradation

Hollow covalent organic framework microsphere (H-COF-OMe) using TAPB and DMTP with enriched interfacial defects was fabricated via emulsion interfacial polymerization and in turn applied as a novel host for high laccase loading and tetracycline (TC) degradation. Benefited from the space-confined growth in the multiphase solvent interface, H-COF-OMe exhibited hollow spherical microstructure, high surface area and unique defects-rich interface. Attributed to these intriguing aspects, H-COF-OMe achieved maximum loading capacity of 567 mg/g and activity recovery of 85% for laccase. H-COF-OMe efficiently stabilized the active conformation of laccase from structural distortion via multiple binding sites, which endowed [email protected] significantly higher pH, thermal, and storage stabilities, and reusability than free laccase and [email protected] Interestingly, the hollow morphology and defective interface of [email protected] accelerated the diffusion of TC and shortened the reaction pathway, which endowed it with markedly enhanced TC degradation and recycling performance than many state-of-the-art catalysts. Significantly, [email protected] (20 mg) could achieve 99% degradation of 50 mg/L tetracycline (50 mL) within 100 min. Monitoring of the intermediate products indicated that [email protected] showed outstanding detoxification performance of the degradation products. This work suggested a novel COF synthesis strategy as laccase immobilization supporters for high TC degradation, which makes it as a promising candidate for degradation of organic pollutants.