Biodegradable MOFilters for Effective Air Filtration and Sterilization by Coupling MOF Functionalization and Mechanical Polarization of Fibrous Poly(lactic acid)

Abstract

High-performance air filtration materials are important for addressing the airborne pollutants. Herein, we propose an unprecedented access to biodegradable poly­(lactic acid) (PLA)-based MOFilters with excellent filtering performance and antibacterial activity. The fabrication involved a stepwise in situ growth of zeolitic imidazolate framework-8 (ZIF-8) crystals at the surface of microfibrous PLA membranes, followed by mechanical polarization under high pressure and low temperature (5 MPa, 40 °C) to trigger the ordered alignment of dipoles in PLA chains and ZIF-8. The unique structural features allowed these PLA-based MOFilters to achieve an exceptional combination of excellent tensile properties, high dielectric constant (up to 2.4 F/m), and enhanced surface potential as high as 4 kV. Arising from the remarkable surface activity and electrostatic adsorption effect, a significant increase (from over 12% to nearly 20%) in PM0.3 filtration efficiency was observed for the PLA-based MOFilters compared to that of pure PLA counterparts, with weak relation to the airflow velocities (10–85 L/min). Moreover, the air resistance was controlled at a considerably low level for all the MOFilters, that is, below 183 Pa even at 85 L/min. It is worth noting that distinct antibacterial properties were achieved for the MOFilters, as illustrated by the inhibitive rates of 87 and 100% against Escherichia coli and Staphylococcus aureus, respectively. The proposed concept of PLA-based MOFilters offers unprecedented multifunction integration, which may fuel the development of biodegradable versatile filters with high capturing and antibacterial performances yet desirable manufacturing feasibility.

Improved Antibacterial Properties of Polylactic Acid-Based Nanofibers Loaded with ZnO–Ag Nanoparticles through Pore Engineering

“…We conducted a comparison between our prepared porous antibacterial PLA-based fiber materials and existing porous PLA fibers in terms of antibacterial property, hydrophobicity, and mechanical property (Table S3). − The results revealed that the current porous PLA fiber materials face challenges in simultaneously achieving good antibacterial property, hydrophobicity, and mechanical property. However, our work demonstrated that the porous PLA-based fibers possess excellent antibacterial property, good hydrophobicity, and mechanical property.…”

Biodegradable Electroactive Nanofibrous Air Filters for Long-Term Respiratory Healthcare and Self-Powered Monitoring

“…In addition, we assessed the filtration performance of PLA FMs on cigarettes. We chose cigarettes as the smoke source because the potential respiratory risks associated with nicotine and other constituents of cigarettes pose various threats to human health . The PLA FMs were fixed and sealed between the membrane modules, while cigarettes were lit during the tests.…”

“…We chose cigarettes as the smoke source because the potential respiratory risks associated with nicotine and other constituents of cigarettes pose various threats to human health. 9 The PLA FMs were fixed and sealed between the membrane modules, while cigarettes were lit during the tests. The concentrations of smoke were measured before and after passing through the membrane using a particle counter (HT-9600, Xintai Instrument, China), with a filtration time set to 120 s. A control sample was made using a meltblown polypropylene fabric as obtained from the intermediate filter layer of an N95 respiratory mask (N95, 3M Co., Ltd., USA).…”

“…Among the available biodegradable polymers, poly­(lactic acid) (PLA) is one of the most representative candidates due to its good biodegradability, desired renewability, high mechanical properties, and ease of processing. , Recent efforts have been made to facilitate the development of PLA-based membrane filters, e.g., Wang’s group developed melt-blown PLA nonwovens with a filtration efficiency of 94.63% for PM 0.3 by graded control of high-temperature and high-speed airflow, while Meng and co-workers fabricated PLA bead-on-sting nanofibrous membranes (NFMs) exhibiting removal efficiencies of 92.6% for PM 2.5 and 95.4% for PM 10 in a real hazy environment . However, the PLA membrane filters are generally characterized by ineffective filtration of PMs and rapid decay of filtration efficiency due mainly to the relatively low dielectric constant (2.3–3.1), poor polarization effect, low capability of charge storage, and thus insufficient electret properties.…”

ZIF-8/Curcumin-Loaded Electrospun Nanofiber Membrane for Wound Healing

“…Notably, when ZIF-8 disintegrates, it continuously releases Zn 2+ , which is an excellent antibacterial agent. Numerous studies have demonstrated that using the original ZIF-8 or nanocomposites based on ZIF-8 may prevent bacterial invasion and facilitate pathogen removal, thereby preventing bacterial infection during the wound-healing process. − However, ZIF-8 is typically obtained in the form of a fragile microcrystalline powder, which limits its applicability to use as a dressing for treating skin wounds.…”