The particle filtration of an electret media is attributed to the mechanical capture and the electrostatic attraction of particles [31,32]. Many previous studies associated the deteriorated performance of disinfection-treated respirators with the loss of electrostatic charges [7,9,11,15,17,18,19,22,25], yet the direct evidence of charge deterioration was often missing. Additionally, it has hardly been examined for the effect of treatment on the structural integrity of the filter media, which may affect the resistance of respirators. This study aims at divulging the effects of disinfection treatments on inactivation/removal of bacteria, deterioration of filtration performance and structural integrity. To this end, commonly-applied disinfection methods were employed as reuse treatments of respirators, which included microwaving, oven-dry, UV irradiation, immersions in hypochlorite (ClO−), ethanol (EtOH), and isopropanol (IPA), and laundering with and without detergent. The influence of disinfection treatment on bactericidal effect was investigated using Escherichia coli (E. coli) bacteria, as a common Gram-negative bacteria with viability in diverse environments [33]. The change of filtration performance after treatments and the probable causes for the change were examined by measuring surface potential, wettability, chemical property, and the morphology of filter fibers. The approach of this study is significant in that the validity of various disinfection methods were extensively investigated, associating the deteriorated performance with the physicochemical changes of electret media after treatments. Rarely has it been conducted for this level of inclusive investigation to reveal the impact of disinfection treatments. This study intends to provide practical yet fundamental information on the effect of disinfection treatments in multifarious aspects including bactericidal and filter performance.