Abstract
Hybrid poly(lactic acid)/titania (PLA/TiO2) fibrous membranes exhibiting excellent air filtration performance and good antibacterial activity were prepared via the electrospinning technique. By varying the composition of the precursor solutions and the relative humidity, the morphologies of PLA/TiO2fibers, including the nanopores and nanometer-scale protrusions on the surface of the fibers, could be regulated. The distribution of nanopores and TiO2nanoparticles on the surface of PLA/TiO2fibers was investigated. Nitrogen adsorption-desorption analysis revealed that nanopores and nanometer-scale protrusions play an important role in improving the specific surface area and nanopore volume of the relevant PLA/TiO2fibrous membrane. Filtration performance tests conducted by measuring the penetration of sodium chloride aerosol particles with a 260 nm mass median diameter indicated that fibers with a high surface roughness, large specific surface area, and large nanopore volume greatly improved the particle capture efficiency and facilitated the penetration of airflow. Furthermore, the introduction of TiO2nanoparticles endows the relevant fibrous membrane with antibacterial properties. The as-prepared PLA/TiO2fibrous membrane loaded with 1.75 wt% TiO2nanoparticles formed at a relative humidity of 45% exhibited a high filtration efficiency (99.996%) and a relatively low pressure drop (128.7 Pa), as well as a high antibacterial activity of 99.5%.
Highlights
Particulate matter pollution has drawn increasing attention because it may cause serious health problems, such as respiratory diseases, cardiovascular illness, and allergies [1,2,3]
By increasing the TiO2 contents, the surface structure of the hybrid poly(lactic acid) (PLA)/TiO2 fibers was remarkably changed by creating nanometer-scale rough structures with additional TiO2 nanoparticles (TiO2 NPs) attached onto the surface of fibers without sacrificing the nanopores and the fiber diameters of PLA/TiO2-0.5, PLA/TiO2-1, PLA/TiO2-1.5, PLA/TiO2-1.75, and PLA/TiO22 slightly increased from 1.29 μm to 1.40 μm with a gradually increasing diameter deviation, which could be ascribed to the weakened conductivity and enhanced viscosity of the composite solutions (Table 1)
It can be observed that when the TiO2 concentration was no more than 1.75 wt%, the TiO2 NPs were relatively evenly distributed on the surface of the fibers, while, as the TiO2 concentration reached 2 wt%, micron-sized agglomerates formed on the fiber surface, which was related to the agglomeration of TiO2 NPs and the interaction between TiO2 NPs and the PLA fibers
Summary
Particulate matter pollution has drawn increasing attention because it may cause serious health problems, such as respiratory diseases, cardiovascular illness, and allergies [1,2,3]. Electrospun nanofibrous membranes exhibit fascinating features, including large specific surface area, high porosity, small pore size, and good interconnected pore structure, which is conducive to the capture of fine particles [15,16,17] Exploiting these characteristics, many types of electrospun fibrous membranes have been fabricated as air filtration media. The most common of these are the Journal of Nanomaterials homogeneous and single-structured nanofibers, including ultrafine Nylon 6 fibers, polyethylene oxide nanofibers, and alumina nanofibers, which have a circular cross section and a relatively smooth surface [18,19,20] These nanofibrous membranes possess high filtration efficiency for fine particles, but they typically have an excessive pressure drop
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