Dual functional biodegradable PLA/ZIF-67 nanofiber air filter for instantaneous removal of toluene and particulate...

The widespread use of non-degradable polymer-based air filters, such as HEPA, poses serious environmental concerns due to their persistence after disposal. In contrast, poly(lactic acid) (PLA) offers a sustainable alternative with demonstrated biodegradability. In this study, we present the fabrication of a fully biodegradable air filter based on PLA nanofibers functionalized with zeolitic imidazolate framework (ZIF-67) for high-efficiency particulate matter and volatile organic compound (VOC) removal. Electrospun PLA nanofibers (PNF) were deposited onto a PET substrate, with spinning volumes of 2, 4, and 6 mL (PNF-2, PNF-4, and PNF-6, respectively). These filters achieved remarkable PM_2.5 filtration efficiencies of 99.22 %-99.36 % at a high face velocity of 1.6 m/s, significantly outperforming the bare PET filter (5 %). To further enhance VOC capture, ZIF-67 was grown in situ on the nanofibers to produce PZNF-2, PZNF-4, and PZNF-6. Among these, PZNF-6 exhibited the highest toluene adsorption capacity of 161 mg/g under dynamic conditions. Most notably, enzymatic degradation studies revealed complete (100 %) disintegration of the PLA nanofiber matrix within 24 h, highlighting the material's rapid and environmentally friendly disposal profile. This work not only demonstrates the synergy of MOF-functionalized biodegradable nanofibers for dual air purification functions, PM filtration and VOC adsorption but also addresses the critical need for sustainable end-of-life filter solutions. The presented strategy offers a compelling alternative to conventional synthetic filters by combining high performance with ecological responsibility.