Hierarchical three-layered fibers for bioaerosol and CO2 capture, and antimicrobial performance

Abstract

As the duration of indoor activities has increased owing to environmental issues and the prevalence of respiratory diseases, it has become important to reduce indoor air pollutants. In this study, air filters with structurally modified surfaces are fabricated to effectively capture and remove indoor air pollutants. High-temperature alkali treatment is applied to a smooth fiber filter to convert it into porous calcium silicate hydrate and create a hierarchical three-layered (H3L) fibrous structure. The outer, middle, and inner layers of the H3L fiber are designed for bioaerosol capture and disinfection, CO2 capture, and maintenance of mechanical strength, respectively. An antimicrobial agent ((3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride, TPMMC) is covalently grafted onto the surface of H3L fibers to impart antimicrobial performance. The H3L-TPMMC filter outperforms the bare filter in capturing E. coli and S. aureus aerosols, displaying improved quality factors of 31.9 % and 63.9 %, respectively. It achieves a 99.999 % reduction and 99.790 % for the collected E. coli and S. aureus aerosols, respectively. The H3L-TPMMC filter demonstrates selective CO2 capture and maintains consistent performance and antimicrobial efficacy even in environments with bioaerosols and CO2. This hierarchical filter membrane provides an efficient approach for reducing various indoor air pollutants using a single filter system.