Enhancement of disinfection effect of plasma-generated high valence NO_x by water mist

High valence NO_x generated by hybrid plasma configurations are promising for environmental disinfection, yet their practical applications face limitations. Dry disinfection using high-concentration gaseous high valence NO_x risks air pollution, while spraying plasma-activated water (PAW) suffers from uneven coverage and prolonged treatment times. This paper utilizes a hybrid plasma configuration to generate plasma-activated gas (PAG) rich in high valence NO_x, which is then combined with water mist for surface disinfection. Experimental results demonstrate that PAG-driven mist achieves complete inactivation of methicillin-resistant S. aureus and E. coli in the shortest time compared to direct PAG exposure or atomized PAW. Pre-spraying deionized water mist followed by PAG achieves comparable efficacy to PAG-driven mist, suggesting synergistic gas-liquid interactions. Mechanism analysis reveals that water mist maximizes the utilization of gaseous reactive species in PAG, enabling surface enrichment of aqueous reactive species (e.g. ONOO^-, O₂^-). Scanning electron microscopy and biomolecule leakage assays confirm bacterial membrane disruption as the primary inactivation pathway. Notably, PAG-driven mist absorbs most gaseous O₃ and NO_x with minor post-treatment residues. This paper reveals that water mist can enrich high valence NO_x due to its high solubility, thus achieving high-level and low-pollution disinfection, advancing plasma technology for environmental and medical sterilization.