Plasma-Activated Water: Physicochemical Properties, Generation Techniques, and Applications

Abstract

Plasma-activated water (PAW) is water that has been treated with atmospheric pressure plasma. Due to the presence of reactive oxygen and nitrogen species (RONS), PAW can be used in various applications such as (1) surface disinfection and food decontamination, (2) enhancement in seed germination, and (3) enhancement in surface cooling in the nucleate boiling regime. Briefly, for surface disinfection, the reactive species in PAW can induce oxidative stress on microbes; for enhancement of seed germination, the reactive species in PAW can trigger seed germination and provide nutrients; for enhancement in surface cooling, the reactive species cause a reduction in the surface tension of PAW, facilitating the phase-change heat transfer and, quite unexpectedly, minimizing the surface oxidation. Here, we review the physicochemical properties of PAW, the three commonly used techniques (plasma jet, dielectric barrier discharge, and corona discharge) for generating atmospheric pressure plasma, and the use of PAW for the above three applications. In particular, we review the recent development of the miniaturization of the plasma generator integrated with an acoustic neutralizer to produce plasma-activated aerosols, elimination of the need for storage, and the interesting physicochemical properties of PAW that lead to cooling enhancement.

Innovative Curved-Tip Reactor for Non-Thermal Plasma and Plasma-Treated Water Generation: Synergistic Impact Comparison with Sodium Hypochlorite in Dental Root Canal Disinfection

“…Preclinical and clinical studies have reported that the separate application of NTP and PTW promotes anti-inflammatory and microbicidal functions, facilitating tissue repair and contributing to the restoration of periodontal tissue. The extent of this recovery is contingent on the number of applications, as supported by research such as [49][50][51][52]63,64].…”

Possible Approaches to Studying the Influence of Magnetic Fields and Mechanical Effects on the Physicochemical Properties of Aqueous IgG Colloids

“…In such water, there are peaks in the region of 150-200 nm, with low light scattering intensity. It was previously shown that with prolonged contact of freshly distilled water with atmospheric gases, the water becomes saturated with oxygen and nitrogen molecules [35]. In this case, nano-sized clusters of gases, so-called bubstons, are formed in water [36].…”

Analyses of the Chemical Composition of Plasma-Activated Water and Its Potential Applications for Vaginal Health

“…The disinfection effectiveness of PAW hinges upon the concentration of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the PAW. ROS generated in PAW, including hydrogen peroxide(H 2 O 2 ), hydroxyl radical(•OH), and ozone (O 3 ), function as potent oxidizing agents, inducing oxidative stress on the microbial cell membranes and, consequently, bacterial damage and death [7].…”

“…Peroxynitrite can accumulate inside cells leading to apoptotic or necrotic cell death [8]. The production of various reactive oxygen and nitrogen species (RONS) depends on the operating parameters of plasma generation, such as the power source, treatment time, feed gases, and electrode materials [7,9]. Gao et al reported that increasing the electrical power from 0 to 160 W led to higher concentrations of OH, H 2 O 2 , NO 3 − , and NH 4 in PAW [4].…”