Efficacy and mechanism of inactivation of bacterial aerosols by non-thermal plasma
To address the issue of indoor bacterial aerosol transmission and ensure air biosafety,an experiment was conducted utilizing E.coli and Bacillus subtilis.as model strains,with non-thermal plasma employed as a means of sterilization.The study investigated the impact of input voltage,carrier gas flow rate,and initial concentration on the efficiency of bacterial aerosol inactivation.Analysis of OES,EPR,and biological characterization results revealed that reactive species(primarily including 1O2,O2-,·OH)generated by non-thermal plasma during the inactivation process disrupted the bacteria's cell membrane leading to protein leakage,breakdown of lipids and nucleic acids ultimately resulting in complete bacterial inactivation.Increasing input voltage while decreasing flow rate could improve inactivation efficiency.However,when the initial concentration increased to a threshold,the improvement on the inactivation efficiency was negligible.The resistance of the two bacteria aerosols inactivated by non-thermal plasma was:Bacillus subtilis>E.coli.Specifically,Bacillus subtilis demonstrated an inactivation rate constant(k)of 0.0038L/J along with an energy efficiency value of 0.027(kW·h)/m3;whereas for E.coli these values were measured at 0.0043L/J and 0.021(kW·h)/m3 respectively indicating that non-thermal plasma was more effective against gram-negative bacteria such as E.coli.
non-thermal plasmabacteriabioaerosolinactivation mechanismreactive species
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