A Novel Method for Fabricating an Electrospun Poly(Vinyl Alcohol)/Cellulose Nanocrystals Composite Nanofibrous Filter with Low Air Resistance for High-Efficiency Filtration of Particulate Matter

Abstract

Particulate matter (PM) air pollution poses a risk to public health, especially in rapidly industrializing countries. One major way to protect individuals from PM exposure is to use fiber-based filters for indoor air purification. In this study, a new low pressure drop poly­(vinyl alcohol) (PVA)/cellulose nanocrystals (CNCs) composite nanofibrous filter was fabricated using electrospinning. This electrospun PVA/CNCs filter was demonstrated as an air filter for the first time. The CNCs not only contributed to the PVA/CNCs system as mechanical reinforcement agents but also increased the surface charge density of the electrospinning solution, thereby reducing fiber diameter. The thinner fibers reduced pressure drop significantly and increased the efficiency of PM removal. Our results indicate that high PM2.5 removal efficiency was achieved (99.1%) under extremely polluted conditions (PM2.5 mass concentration > 500 μg m–3) with low pressure drop (91 Pa) at an airflow velocity of 0.2 m s–1. Considering that PVA and CNCs are both nontoxic and biodegradable, this high-efficiency composite filter with low air resistance is environmentally friendly and shows promise in indoor air purification applications.

Face Masks in the New COVID-19 Normal: Materials, Testing, and Perspectives

“…The developed transparent thin filter can be applied to indoor air protection through windows or incorporated into existing personal masks. Inspired by Lui's promising results, a variety of electrospun nanofibre membranes with different surface chemistry and mechanical or thermal properties have been developed from polymers, polymer blends, or polymer composites with surface-functionalized inorganic nanofillers for air purification investigations, including polyurethane [ 127 ], polycarbonate [ 128 ], poly(vinyl alcohol) [ 129 ], polytetrafluoroethylene [ 130 ], polybenzimidazole [ 131 ], polyacrylonitrile/polysulfone [ 132 ], polypropylene/polyethylene [ 133 ], polyurethane/polysulfonamide [ 134 ], polyacrylonitrile/graphene oxide [ 135 ], and polyacrylonitrile/MXene [ 136 ]. Besides conventional electrospinning, polymer nanofibre membranes mass-produced by needless electrospinning [ 137 ] and solution blow spinning [ 138 ] also demonstrated effectiveness for the capture of particulate pollutants.…”

Design of Web-to-Web Spacing for the Reduced Pressure Drop and Effective Depth Filtration

“…Argumentatively, another study reported nanofibers in 60–100 μm can produce the “slip effect”, by which the frictional force between air molecules and fibers were reduced. The studies demonstrated the “slip effect” by the simulated work, and reported that the nanofibers in this size range are beneficial for decreasing the resistance [17,43,44,45]. However, the application of those studies may be limited because only the initial pressure drop has been considered.…”

Reversible swelling as a strategy in the development of smart membranes from electrospun polyvinyl alcohol nanofiber mats

“…The need for an approach that alleviates concerns related to safety, toxicology, and environmental problems has generated interest in “green” electrospinning processes. For some water‐soluble polymers, electrospinning can be performed in aqueous solutions, and a water‐resistant membrane is then achieved using an environmentally friendly crosslinker and a post‐manufactured treatment . Despite being water‐resistant, these membranes remain hydrophilic and can also swell in water.…”