Integrated Transport Model for Controlled Delivery of Short-Lived Reactive Species via Plasma-Activated Liquid with Practical Applications in Plant Disease Control

Abstract

Gas–liquid interfacial plasmas (GLIPs), specifically atmospheric-pressure plasmas (APPs) interacting with liquids, have garnered global interest for potential applications across various fields where reactive oxygen and nitrogen species (RONS) in both the gas and liquid phases could play a key role. However, APP-induced gas- and liquid-phase chemical reactions display spatially nonuniform features and involve a number of species; thus, they are extremely complicated and have not been fully understood and controlled. Herein, our primary focus is centered on elucidating RONS transport processes in GLIPs without direct plasma-liquid contact to reduce the complexity of this mechanism. Firstly, this review delineates the simplified transport models commonly found in general GLIP systems, including: (1) the transport of remotely generated gas-phase RONS to the liquid phase; (2) liquid-phase diffusion governing dissolution into the liquid phase and volatilization loss to the gas phase; and (3) chemical reactions in the liquid phase governing the generation and loss of short-lived RONS. Second, we delve into RONS transport using our laboratory-built plasma devices, aimed at sterilizing plant pathogens, interpreting results in line with the relevant transport models to aid the comprehension of the heterogeneous transport of RONS. Third, we discussed the innovative control of the plasma reaction process in the gas phase required to selectively synthesize N2O5, which is highly reactive at the gas–liquid interface. Finally, future prospects for the efficient utilization of unique reactions at the plasma/gas–liquid interface are discussed.