Humidification effect of air plasma effluent gas on suppressing conidium germination of a plant pathogenic fungus in the liquid phase

• Published in: Plasma processes and polymers 2020-01, Vol.17 (1), p.n/a
• Main Authors: Shimada, Keisuke, Takashima, Keisuke, Kimura, Yutaka, Nihei, Kenji, Konishi, Hideaki, Kaneko, Toshiro
• Format: Article
• Language: English
• Subjects: Air plasma; air plasma effluent; Antiinfectives and antibacterials; dielectric barrier discharges; Effluents; Flow velocity; Fungi; Gas cooling; Germination; Humidification; Latent heat; Liquid phases; Liquid surfaces; Plasma; plasma agricultural applications; Precursors; Surface reactions; Vapor phases; Water flow
• ISSN: 1612-8850; 1612-8869
• DOI: 10.1002/ppap.201900004

Increase of the water flow rate into atmospheric pressure air discharge plasma for humidification can significantly improve suppressing conidium germination of a plant pathogenic fungus in the liquid phase by its effluent gas exposure. The role of the introduced water includes enhancement of hydrogen supply to the plasma and cooling of the plasma effluent gas. The hydrogen‐containing precursors for antibacterial species generation are experimentally increased. The gas cooling by the latent heat assists dinitrogen pentoxide density in the gas phase, a suggested precursor for antibacterial species generation near the liquid surface. This suggested near‐surface reaction is a second‐order reaction, generally requiring lower precursors concentrations and leading to less residues, thus it can be an important process for agricultural applications. Humidified air plasma effluent gas generated by dielectric barrier discharge (DBD) plasma significantly suppresses conidium germination of a plant pathogenic fungus far downstream from the DBD plasma. The higher water flow rate into the DBD plasma, composing dinitrogen pentoxide and enhancing the molecular transfer rates into the liquid phase, significantly improves the germination suppression effect.