Experimental study on the inactivation of bioaerosols by dielectric barrier discharge combined with Ag-Cu/TiO2-CS composite photocatalyst
Escherichia coli and Aspergillus niger were selected as model organisms to prepare typical bacterial and fungal aerosols,respectively.A chitosan(CS)-modified Ag-Cu/TiO2-CS composite photocatalyst was synthesized via the sol-gel method.The efficacy of this photocatalyst,in conjunction with a custom-built cylindrical dielectric barrier discharge(DBD)reactor,was assessed for bioaerosol inactivation.The study examined the impact of initial concentration,discharge power,and the synergy between photocatalytic and plasma treatments on bioaerosol deactivation.Mechanistic insights were garnered through SEM analysis,as well as extracellular protein and electrolyte assays.The optimal bactericidal effect was achieved with an Ag and Cu doping ratio of 2:2mol％,resulting in a 0.61-lg reduction in E.coli viability within 10.5seconds.Compared to standalone DBD treatment,the combined approach significantly enhanced bacterial and fungal inactivation rates to 2.89-lg and 2.87-lg,respectively,under a 60W condition,and substantially inhibited bioaerosol revival.Post-inactivation,the revival rates of bacteria and fungi were reduced to-3.40-lg and-3.39-lg,respectively,within 48 hours,underscoring the enhanced efficiency of the synergistic treatment.
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