Deactivation of airborne bacteria, fungi, and viruses by microwave absorption material Fe₃O₄@SiCcf

Abstract

This study aims to provide a comprehensive summary of the inactivation of airborne Escherichia coli [(E. coli), a gram-negative bacterium], Bacillus subtilis [(B. subtilis), a gram-positive bacterium], MS2 (a bacteriophage) virus, and Aspergillus versicolor [(A. versicolor), a fungus] with kinetic analysis utilizing microwave irradiation based on absorption material. The capacity of a microwave-absorbing material Fe₃O₄@SiC ceramic foam (Fe₃O₄@SiCcf) to inactivate bioaerosols when subjected to microwave (MW) irradiation (2450 MHz) for 25 seconds at various output powers (750, 550, 350, and 150 W) was determined. The airborne MS2 decreased by 4.5 logs at the microwave (MW) input energy density of 7.2 × 10³ kJ/m³, while that for E. coli was at around 4.4 logs, and that for B. subtilis was at 4.3 logs. The activation energy (Ea) applied was 13.2 kJ/mol (E. coli), 14.6 kJ/mol (B. subtilis), and that for MS2 virus was 9.6 kJ/mol. By contrast, this study has shown that A. versicolor log inactivation efficiency was lower and Ea was higher than others, which were 3.6 logs and 16.7 kJ/mol, respectively. In addition, MW - Fe₃O₄@SiCcf improved the inactivation efficiency of airborne microorganisms significantly compared with no absorbing material. Through the comparative analysis of energy consumption, the rate of constant airborne inactivation through MW irradiation is higher than UV and Fenton. However, the energy efficacy per MW irradiation order is lower. In summary, Fe₃O₄@SiCcf ceramic form is an energy-efficient material for inactivating airborne microorganisms under MW irradiation.

Copyright © 2022 American Association for Aerosol Research

Graphical Abstract

EDITOR:

• Shanna Ratnesar-Shumate

Additional information

Funding

This research was supported by the Key Technologies R & D Program of Tianjin (21JCZDJC00580).