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

High valence NOx generated by hybrid plasma configurations are promising for environmental disinfection, yet their practical applications face limitations. Dry disinfection using high-concentration gaseous high valence NOx 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 NOx, which is then combined with water mist for surface disinfection. Experimental results demonstrate that PAG-driven mist achieves complete inactivation of methicillin-resistant Staphylococcus aureus (MRSA) 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 NOx with minor post-treatment residues. This paper reveals that water mist can enrich high valence NOx due to its high solubility, thus achieving high-level and low-pollution disinfection, advancing plasma technology for environmental and medical sterilization.