Engineering a hierarchical porous aerogel from TCNF and diatomite for superior air filtration and antibacterial performance

The integration of multiple functions into a single air filtration material is a critical goal for next-generation protective equipment, yet achieving a harmonious balance between high filtration efficiency, robust antibacterial activity, and mechanical durability remains a significant challenge. Here, we report the first scalable and eco-friendly fabrication of a TEMPO-oxidized cellulose nanofibril (TCNF)-based composite aerogel that uniquely integrates these three essential properties. By using TCNF as a sustainable skeleton and strategically incorporating diatomite (DM) for structural reinforcement, Ag nanoparticles for antibacterial action, and methyltrimethoxysilane (MTMS) for hydrophobic modification, we construct a lightweight, highly elastic aerogel via freeze-drying. The resulting material achieves a remarkable PM2.5 filtration efficiency of 98.3% and a quality factor of 0.057 Pa⁻¹ , while simultaneously demonstrating over 99.9% bactericidal efficiency against E. coli. Crucially, this performance is underpinned by outstanding mechanical stability, with the aerogel exhibiting recoverable compressibility up to 80% strain and excellent fatigue resistance. By resolving the traditional trade-off between these functions using a renewable and environmentally friendly platform, this work presents a promising new pathway toward greener, safer, and more sustainable high-performance air filtration solutions. • Eco-friendly strategy fabricates multifunctional TCNF-based composite aerogels. • Aerogel shows excellent filtration, antibacterial and mechanical properties. • Renewable materials enable sustainable air filtration solutions.