Biodegradable Cellulose Acetate Nanofibrous Membranes with Self-Sustaining Electrostatic Effect for Efficient and Stable Air Purification

Amid the global pursuit of carbon neutrality and the pressing challenge of severe air pollution, degradable cellulose acetate (CA) materials hold great potential in the field of air filtration. However, their weak polarity and poor antibacterial properties limit their widespread application in this field. Herein, we developed CA-based nanofibrous membranes (CAPZ NFMs) with antimicrobial properties, which achieved efficient and stable filtration performance through a self-sustaining electrostatic effect driven by polarity. CAPZ NFMs were fabricated by electrospinning a solution that contained CA, highly polar zwitterionic copolymers (PSG), and biocompatible Zr⁴⁺. The zwitterionic groups of PSG increased the polarity of CAPZ NFMs to 19.62 mN·m^-1, significantly surpassing that of pristine CA NFMs (2.94 mN·m^-1). This enhancement granted CAPZ NFMs a surface potential of 2.07 kV, which enabled a PM_0.3 filtration efficiency of 99.56% while maintaining a low pressure drop of 79 Pa. Notably, CAPZ NFMs maintained superior performance under high humidity conditions and 6 months of outdoor storage. Additionally, Zr⁴⁺ coordinated with the zwitterionic groups of PSG to form quaternary ammonium groups, endowing CAPZ NFMs with broad-spectrum antibacterial efficacy of over 99.99%. This work could provide new strategies for developing next-generation biodegradable, high-electrostatic filtration materials.