Efficient, Breathable, and Compostable Multilayer Air Filter Material Prepared from Plant-Derived Biopolymers

Area of Science:

• Materials Science
• Environmental Science
• Biotechnology

Background:

• Conventional face masks and respirators are typically single-use polypropylene devices, posing significant waste management and recycling challenges.
• The need for sustainable alternatives to reduce the environmental impact of personal protective equipment is growing.

Purpose of the Study:

• To develop a novel compostable air filter material for face masks and respirators.
• To enhance the humidity tolerance and mechanical durability of the filter material.
• To optimize the filter's performance in terms of particle filtration efficiency (PFE) and pressure drop (PD).

Main Methods:

• Electrospinning of zein, a plant-derived protein, onto a craft paper substrate.
• Crosslinking zein with citric acid to improve humidity tolerance and mechanical durability.
• Fabrication of pleated filter structures to enhance breathability without compromising filtration.

Main Results:

• The electrospun zein material achieved a PFE of 91.15% and a PD of 191.2 Pa for 75 nm particles at 10 cm/s.
• Pleated filter structures significantly reduced pressure drop (e.g., 28.9 to 39.1 Pa for single-layer over 1h salt loading) compared to flat filters (169.3 to 327 Pa).
• A two-layer pleated filter (5 mm pleat width) demonstrated a PFE of 95.4 ± 0.34% with a low PD of 75.2 ± 6.1 Pa.

Conclusions:

• A compostable, plant-derived air filter was successfully developed using electrospun zein.
• The crosslinked zein material offers a promising sustainable alternative for air filtration applications.
• Pleating strategies effectively improved breathability while maintaining high particle filtration efficiency, addressing key performance metrics for face masks.