High‐Efficiency PLA Nano‐Microfibrous Filters Enabled by Bimodal Structure and Corona Discharge

ABSTRACT Air pollution is a pressing issue for environmental sustainability and human health, with air filters playing a pivotal role in mitigating its effects. However, conventional polymer‐based air filters pose environmental challenges. This study focuses on developing biodegradable poly(lactic acid) fibrous unimodal and bimodal filter webs using electro‐blowing (EB) and solution‐blowing (SB) techniques. Fiber diameters were controlled by adjusting solution concentrations (10% and 20% w/w) and applying an electric field during production. EB with low‐concentration solutions produced nanofibers (Y) averaging 0.14 μm, while SB with high‐concentration solutions yielded fibers (X) around 1.60 μm. Bimodal fibrous webs exhibited a dual‐peak distribution with diameters centered at 0.17 and 1.56 μm. Filtration tests at a 95 L/min air flow rate for PM 0.3 particles revealed that the EB sample had the highest filtration efficiency (96.562%) and airflow resistance (177 Pa). Among bimodal configurations, X + Y, with nano/microfibers collected simultaneously, demonstrated the best quality factor (98.604% efficiency and 146 Pa Δ P ). Corona discharge treatment further enhanced filtration efficiency, with the X + Y sample achieving 99.997% efficiency. After a week of repetitive testing, X + Y maintained high performance with 99.972% efficiency and a 192 Pa Δ P . These findings highlight PLA filters' potential as sustainable and efficient air filtration solutions.