Alternative High-Performance Fibers for Nonwoven HEPA Filter Media

Abstract

Continual research, development, and advancement in air filtration technology is important to abate the ever increasing health hazards of air pollution and global pandemics. The purpose of this review is to survey, categorize, and compare mechanical and thermal characteristics of fibers to assess their potential applicability in air filter media. The history of high-efficiency particulate air (HEPA) filter development explains how we arrived at the current state of the art nonwoven fibrous borosilicate glass filter paper. This review explores the history and practical uses of particular fiber types and explains fiber production methods in general terms. The thermal and mechanical properties of particular fibers are examined using the codes and standards produced by the American Society of Mechanical Engineers (ASME) to generalize the applicability of fiber categories for HEPA filter units within the nuclear air cleaning industry. This review discusses common measurements for specific strength and tenacity used by the textile and construction industries. Particular fibers are selectively compared for density, tensile strength, tensile stiffness, flexural rigidity, moisture regain, decomposition temperature, and thermal expansion. This review concludes with a subjective assessment of which types of fibers may be appropriate to study for HEPA filtration.

Effectiveness of Asthma Home Management Manual and Low-Cost Air Filter on Quality of Life Among Asthma Adults: A 3-Arm Randomized Controlled Trial

“… 48 This fiber can be used as an air filtration medium as well as a HEPA filter because it has a higher melting point. 49 We utilized a 3M Filtrete TM filter with microparticle filtration efficiency rating (MPR) was 1000 and thickness 0.72 mm (in metric) while it can work properly and effectively. 49 , 50 It is also commonly applied in air-conditioner (AC) filtration systems.…”

“… 49 We utilized a 3M Filtrete TM filter with microparticle filtration efficiency rating (MPR) was 1000 and thickness 0.72 mm (in metric) while it can work properly and effectively. 49 , 50 It is also commonly applied in air-conditioner (AC) filtration systems. We propose the application of this filter to the backside of an electric fan as a low-cost air-filtration system.…”

Cellulose Membranes: Synthesis and Applications for Water and Gas Separation and Purification

“…Generally, the mean pore size is directly proportional to the fiber diameter in nonwoven fiber membranes. At the same thickness of membranes, air filtration efficiency and airflow resistance decrease exponentially with fiber diameter but selectivity increases [70]. Generally, smaller diameter fibers lead to a higher number of pores and smaller average pore size.…”

“…Cellulose and its derivatives can be dissolved into solvents. The solutions can be spun into fibers with average diameters from 50 to 900 nm [70], which can form membranes of randomly distributed fibers (e & f). The term nanofiber is usually used to designate those with diameters from 1-100 nm while the term microfiber refers to those with diameters ranging from about 100 nm to 10 µ m. Adjusting electrospinning parameters (e.g., flow rate, applied voltage, coagulation conditions) and formulations of cellulose solutions, the surface chemistry and morphology along with other physiochemical characteristics such as tensile strength of fibers, swelling property, porosity, permeance, and adsorption can be finely tuned for specific pore size and distribution either as the support layer or selective layer.…”

Electrospun Cyclodextrin/Poly(L-lactic acid) Nanofibers for Efficient Air Filter: Their PM and VOC Removal Efficiency and Triboelectric Outputs

“…Another example commercial air filter is high-efficiency particulate air (HEPA) filter, which is the most effective medium to capture particles on a fibrous or porous membrane in an air purifier machine. However, the common filtration media, which is made of fibrous borosilicate glass filter paper, is fragile and has water damage [ 7 ]. In addition, both commercial PP and HEPA filters contain fibers in micron size; thus, they typically have a high thickness, leading to a high-pressure drop.…”