Transparent Air Filters with Active Thermal Sterilization.

Area of Science:

• Materials Science and Engineering
• Nanotechnology
• Public Health

Background:

• The COVID-19 pandemic highlights the need for effective air filtration solutions.
• Existing air filters often lack transparency, hindering communication.
• Sterilizable and reusable filters are crucial for pandemic preparedness.

Purpose of the Study:

• To develop transparent and self-sterilizing air filters using copper nanowires.
• To evaluate the filtration efficiency, transparency, and antimicrobial properties of the novel filters.
• To assess the reusability and thermal stability of the copper nanowire air filters (CNAFs).

Main Methods:

• Fabrication of transparent air filters using copper nanowires (CNAFs).
• Evaluation of particulate matter (PM) capture via mechanical and electrostatic filtration.
• Assessment of visible light penetration for communication.
• Joule-heating for controlled temperature up to 100 °C and thermal stability testing.
• Testing of antimicrobial efficacy against *E. coli* and *G. anodireducens*.
• Evaluation of reusability through repeated filtration and sterilization cycles.

Main Results:

• CNAFs demonstrated visible light penetration, enabling facial expression visibility for communication.
• Effective capture of particulate matter (PM) was achieved through combined filtration mechanisms.
• Antimicrobial activity against *E. coli* was observed due to the oligodynamic effect of copper.
• Heat sterilization significantly enhanced antibacterial efficiency against *G. anodireducens* to 99.3% within 10 minutes.
• CNAFs maintained stable filtration efficiency and thermal antibacterial efficacy after five reuse cycles.

Conclusions:

• Copper nanowire air filters offer a promising solution for transparent, self-sterilizing air filtration.
• The developed CNAFs can inhibit virus transmission while facilitating communication.
• These filters represent a viable, reusable, and active antimicrobial air filter for current and future pandemic scenarios.