Efficient removal of airborne PM_0.3 by surface engineered poly(lactic acid) MOFilters with enhanced electroactivity and surface activity

Fine particulate matter (PMs) is a serious threat to air quality and the ecosystem, so the development of biodegradable and environmentally friendly poly(lactic acid) (PLA) nanofiber filtration membranes has become a hot research topic. In this paper, high specific surface area and high dielectric metal-organic framework MOF-5 crystals with different mass loadings (2%, 4% and 6%) were added to the external-phase spun PLA acid solution and loaded onto PLA nanofibers by coaxial electrospinning technique, and explored the morphology and properties of nanofibrous membranes. The results showed that the fiber diameter of PLA composite nanofibrous membrane containing 2% MOF-5 (PLA@MOF-5-2) was refined to 200 nm, and MOF-5 crystals were embedded in the nanofibers resulted in a 4.3-fold increase in surface potential (5.3 kV), a 2.3-fold increase in friction power output voltage (54.9 V), and an increase in tensile strength of 20% (15.2 MPa). Thanks to the regulation of morphological characteristics and high electrical activity, PLA@MOF-5 nanofibrous membranes showed excellent air filtration performance, the filtration efficiency of PM_2.5 were more than 92%, and the increase of filtration efficiency of PLA@MOF-5 nanofibrous membranes for PM_0.3 could be up to 14.2% when the air flow rate of 85 L/min. Meanwhile, the introduction of MOF-5 increased the surface activity and roughness of PLA fibers, and reduced air resistance. The proposed high-efficiency low-resistance, high-electroactivity PLA@MOF-5 nanofibrous membranes have a broad application prospect in combating air pollution and viral pandemics.