Bacterial cellulose aerogel membrane with ultrafine nanofiber network for efficient PM0.3 filtration

Particulate matter (PM) pollution poses a significant threat to public health, and there is an urgent demand for air filters that can efficiently remove PM. However, achieving high filtration efficiency is often accompanied by a significant increase in air resistance. This efficiency–resistance trade-off presents a major challenge for advancing high-performance filtration membranes. Herein, biodegradable bacterial cellulose aerogel membranes were engineered through freeze-casting technology, utilizing ultra-fine nanofibers (20-30 nm in diameter) with significantly reduced fiber dimensions compared with existing filters, thereby achieving an optimal efficiency–resistance balance in PM filtration. The filter achieves ultra-high PM 0.3 filtration efficiency (>99.99%) and an ultralow pressure drop of only 22 Pa at an airflow rate of 8 L min −1 , corresponding to normal human breathing conditions. Furthermore, a rigid silica layer uniformly coated onto the surface of cellulose nanofibers by chemical vapor deposition technology endowed them excellent elasticity and moisture resistance. Importantly, it can completely decompose in composted soil within 6 weeks. This study provides guidance for the industrial production of biodegradable and moisture-resistant high-performance nanofiber air filters.