Simultaneous Capture and Inactivation of Airborne Bacteria by a Dual-Zone Electrostatically Actuated Filter

Maintaining indoor air quality is essential for human health, and the threat posed by bioaerosols emphasizes efficient capture and inactivation technologies in ventilation systems. However, existing technologies struggle to capture and inactivate bioaerosols simultaneously with low air resistance and integrated technologies make them inconvenient in practical applications. To address this challenge, we developed a dual-zone electrostatically actuated filter in which airborne bacteria are first charged by ions generated in the charging zone and then captured by the polarized fibers and inactivated in the electrostatic field of the polarizing zone. Benefiting from the enhanced electrostatic force, the capture efficiencies for Escherichia coli (Gram-negative) and Staphylococcus epidermidis (Gram-positive) aerosols of 0.3-0.5 mu m diameter increased from similar to 25.4 to similar to 98.4% at 0.5 m/s filtering velocity while the air resistance was maintained at only 4.5 Pa. The capture efficiency remained steadily high for 30 days, with an average of 93.8%. Moreover, the combination of the continued ion flow and electrostatic field exposure significantly improved the inactivation efficiency against E. coli and S. epidermidis to similar to 98.7 and similar to 96.1%, respectively, instead of allowing bacterial reproduction on the coarse filter without electrostatic actuation. The proposed dual-zone electrostatically actuated filter exhibits great potential for incorporation into energy-saving ventilation systems, offering high-efficiency capture and antimicrobial performance as well as low air resistance.