Highly flexible and multifunctional lyocell-basalt fiber filter media for high-performance air filtration

Cellulose-based functionalized fabrics are emerging as promising air purification filter materials. However, limitations such as poor moisture resistance, low strength, and heat sensitivity are challenging in the practical application of fine particulate matter filtration. Here, we developed a flexible and multifunctional lyocell/basalt fiber (LC/BF) filter fabric using a wet-laid process, avoiding the need for additional binders. The filter fabric was further enhanced with ZIF-8 functionalization to achieve considerable PM_0.3 and sulfur dioxide removal. The incorporation of LC fibrillated nanofibers significantly improved the fabric's flexibility, light weight, and filtration performance. The addition of BF reduced pressure drops and significantly increased burst (136.5 %) and tear strength (128.9 %) compared to the pure LC filter media. The BF also helps improve moisture (55.8 %), thermal, and chemical resistance. The resulting LC/BF-25@ZIF-8 fabric demonstrated a remarkable filtration efficiency of 97.72 % for PM_0.3 particles. This functionalization also led to significant enhancements in gas adsorption, specifically 93 % improvement for SO₂ and 111.5 % for the volatile organic compound methylbenzene adsorption, showcasing synergetic simultaneous capture capabilities. Furthermore, excellent antibacterial activity against E. coli, S. aureus, and S. pneumoniae was obtained, with inhibition rates exceeding 99.8-99.9 %. This eco-friendly approach, combining the distinctive properties of LC/BF and ZIF-8, offers a promising solution for multifunctional advanced air filtration applications, such as fitting into sophisticated equipment, combined gas adsorption, and environmental tolerance.