A Micro-nanocomposite Electret Filter for High-Efficiency Particulate Matter Filtration

Abstract

Concerns about indoor air quality (IAQ) have been greatly increased since particulate matter (PM) pollution poses a serious health threat to humans. Particulate air filter is one of the most economical and efficient solutions to PM purification in commercial or residential buildings. In this study, a micro-nanomulti-layer composite electret filter, composed of polystyrene/polyacrylonitrile/polystyrene (PS/PAN/PS) was controllably fabricated via electrospinning. The outer polystyrene (PS) membrane with diameter of 3.93 µm has large pore sizes, which makes the airflow easy to pass. Additionally, the PS media could store a large amount of space charges because of its large basis weight and high insulation resistance. The polyacrylonitrile (PAN) nanofibers laminated between the two PS membranes could enhance the filtration efficiency for fine particles due to its nanoscale diameter. Combined with the advantages of nanoscale fibers and electret materials, the composite filter exhibited a high filtration efficiency (>99.5%) and a low-pressure drop (37 Pa) to sodium chloride (NaCl) aerosol particles (≥0.3 µm) under an airflow velocity of 5.3 cm s−1. The dynamic energy calculation shows that it could save up to 46.38% in energy consumption compared with the traditional commercial ones. The filter is suitable for high-efficiency particulate (HEPA) air filtration in heating ventilation air conditioning (HVAC) systems or stand-alone portable fan-filter air cleaning systems.