# Plasma-Activated Tap Water Production and Its Application in Atomization Disinfection
###### Abstract  
Plasma-activated tap water (PATW) is a new technology for obtaining a high concentration of active aqueous plasma substances by discharging underwater. Commonly plasma-activated water (PAW) is realized by activating deionized water or distilled water, which has problems such as high cost, a small discharge area, and insufficient dissolution of active substances. This paper reports the development of a dielectric barrier discharge array to generate a high concentration of active aqueous plasma substances. The device can realize a uniform, stable, and large-area discharge in a large volume of tap water, and it has the advantages of low cost, high integration, and reusability. Using the device to treat 1000 mL of tap water for 1 h can reduce the pH of the tap water from 8.10 to 2.54, and the logarithmic value of killing E. coli is greater than 5.0. We sprayed PATW onto clothes to sterilize the bacteria when people were through the disinfection door and verified that the PATW had a good sterilization effect. The short-lived substances, singlet oxygen, and superoxide anion radicals played a key role in the sterilization process by PATW.  
plasma-activated tap water; DBD discharge in water; sterilization; singlet oxygen; superoxide anion radical 202313015233015233015230  
a green, clean, safe, and compelling new sterilization and freshness preserving technology. [PERSON] et al. treated distilled water with a dielectric barrier discharge (DBD) to generate PAW and used it to treat _E. coli_ for 15 min. The active bacterial population was reduced by five orders of magnitude [17]. [PERSON] et al. used a DC-driven needle array to activate a chemical solution containing nitrite and hydrogen peroxide, reducing the active _E. coli_ population by 6 orders of magnitude [18].  
There are mainly two methods to generate PAW: discharges on water and discharges in water. The existing PAW preparation systems primarily use water surface discharges and include plasma jets, needle water discharges, surface dielectric barrier discharges, sliding arc discharges, etc. [19; 20; 21; 22; 23]. This method wastes some gaseous RONS and is often used to activate small amounts of deionized or distilled water. When dealing with cheap and readily available tap water, the acid produced by plasma is consumed by the high level of carbonate and bicarbonate in the tap water, which act as buffers, so it is difficult to lower the pH value of tap water [19; 24], resulting in a poor bactericidal effect. In contrast to water surface discharges, discharges in water increase the contact area between the plasma and water significantly and promote the dissolution of the gaseous RONS [25].  
Aiming at the shortcomings of traditional devices, we developed a plasma-activated tap water (PATW) preparation device based on an air dielectric barrier discharge (DBD) in tap water. The plasma generated during the discharge was in direct contact with the tap water through the discharge channel, and the gaseous RONS dissolved easily through the discharge channel and the subsequent bubbling. The high concentration of aqueous RONS had a good bactericidal effect. The atomized PATW was also sprayed onto clothes to sterilize bacteria when people were through the disinfection door. By studying the bactericidal effects of various long-lived and short-lived aqueous RONS, we verified that short-lived singlet oxygen and superoxide anion radical RONS played a key role.