One-step continuous production of ZIFs-decorated fibrous filters for multifunctional gradient filtration with high PM capture and antimicrobial activity

Highly permeable particulate matter (PM), which can carry pathogens and toxin substances, poses a significant public health risk. However, conventional gradient filtration systems still face challenges in capturing sub-micron particles, inactivating microorganisms, and mitigating premature failure of high-efficiency particulate air (HEPA) filters. Therefore, this work develops a scalable, one-step, online production method to prepare multifunctional primary filter media (ZIFs@ES) by the in-situ growth of zeolitic imidazolate frameworks (ZIFs) on fibrous substrates. We employ a through-air process, in which hot air induces the melting and reforming of the bicomponent polyolefin (PE/PP) fibers. This process simultaneously triggers the in-situ growth of ZIF crystals on fiber surfaces, establishing a one-step fabrication method that integrates fiber consolidation with functional coating. By integrating ZIFs@ES with a HEPA filter, we design a multifunctional gradient filtration system (ZIFilters), which exhibits a specific surface area of over 200 m 2 g −1 , compared with 2.18 m 2  g −1 for the ES fibrous substrate. It achieves a PM 0.3 filtration efficiency as high as 99.9% and a bactericidal efficacy of over 99.9%, while maintaining good breathability and mechanical strength. Notably, this process enables continuous production at 300 m h −1 with tunable ZIF phases to meet diverse needs. This strategy offers a practical solution for integrating PM capture and microbial inactivation, extending the application of ZIFilters to air purification and personal protection.