Thermal-resist hydro-charged air filters (HCAFs) with charge stability for long-term efficient fine particle removal

Abstract

Fibrous air filters are widely equipped air freshening material in individual protective masks and air purifiers to regulate air quality and protect people from health hazards. To further improve filtration without increasing airflow resistance, electret technology is commonly used in combination with fibrous air filters due to electrostatic attraction caused by the charges on the fiber. However, constructing fibrous air filters with both charge stability and excellent filtration performance that could be used for long-term particle removal remains a challenge. Herein, hydro-charged air filters (HCAFs) that can be used in long-term high-efficiency removal of sodium chloride and paraffin oil aerosol particles is presented. Specifically, numerious positive and negative charges were dispersed in the HCAFs after hydro charging treatment, resulting in significantly enhanced filtration efficiency of 99.84 % (99.16 %) for sodium chloride (paraffin oil) aerosol particles. More importantly, the filtration efficiency of HCAFs for sodium chloride (paraffin oil) aerosol particles only had a decrement of 2.3 % and 0.35 % (6.1 % and 2.5 %) after 130 ℃ heat treatment and standing for two years, indicating that HCAFs possess charge stability and thermal resistance that can be used for long-term filtration. The successful fabrication of HCAFs shows a great promise for hydro charge technology and provides a new guideline for next-generation commercial air filters.