Biodegradable air filter with electrospun composite nanofibers and cellulose fibers dual network: Enhanced electrostatic adsorption, humidity resistance, and extended service life.

Cellulose-based materials have great potential as degradable air filters. Regretfully, the application is limited by their low electrostatic adsorption and hydrophilicity. To meet with the challenge, we designed a composite air filter with dual network. Composite cellulose acetate nanofibers were electrospun on a cellulose-fibers paper substrate, and the resulted multi-scale spider-web-like structure showed high filtration efficiency as well as low resistance. Electrets (silicon nitride and tourmaline) were composited to enhance the electrostatic adsorption for PMs. Hydrophobic modification improved the ability to retain electrostatic charge, promoting the filtration under humid environment. The filtration efficiency for PM exceeded 99 %, while the pressure drop was only 45.7 Pa. The filtration performance could be maintained for over 12 hours under 90 % relative humidity, and the filter could be completely degraded in natural environment within 80 days.