Optimization of process parameters to generate plasma activated water and study of physicochemical properties of plasma activated solutions at optimum condition

Abstract

Plasma-activated water (PAW) is gaining significant attention these days due to its potential use as a disinfectant, pesticide, food preservative, cancer cell treatment, fertilizer, etc. These applications of PAW depend on its reactivity (oxidizing-potential) and electrical conductivity (EC). In the present work, we have studied the effect of process parameters, viz., air flow rate, water stirrer speed, and the temperature of water during plasma–water interaction on the reactivity and EC of PAW using a three-way full factorial design of experiments. We have also attempted to optimize these process parameters. At optimum values of these parameters, we studied how the physicochemical properties of PAW vary by changing the volume of water and discharge power. Furthermore, we studied the physicochemical properties of the plasma-activated solution (PAS) and how the EC and pH of virgin solutions affect these properties. The obtained results of the present investigation showed that the flow rate of air, plasma treatment time with water, volume of water, and plasma discharge power play a significant role in controlling the reactivity and EC of PAW. Moreover, the pH and EC of virgin solution do not have a significant (p < 0.05) impact on the reactivity of PAS. This investigation also shows the study of aging time on reactive oxygen–nitrogen species and its effect on the physicochemical properties of PAW. Additionally, observed changes in physicochemical properties, NO3− ions, and H2O2 concentration in PAW were less than 10%. However, NO2− ions and dissolved O3 concentration in PAW decreased significantly over time.

Nanosecond‐pulsed microbubble plasma reactor for plasma‐activated water generation and bacterial inactivation

“…[43][44][45][46][47] The oxidation-reduction potential (ORP) represents the net combination of oxidizing species such as NO 3 − , NO 2 − , H 2 O 2, and Ozone dissolved in the PAW. [48] Figure 7 shows the changing trend of ORP at different treatment times and temperatures. Figure 5a-c shows that with the increase of treatment time, all the concentrations of NO…”

Methotrexate degradation in artificial wastewater using non-thermal pencil plasma jet

“…These interact with the solution, changing its chemical properties. The formation of various species and radicals in the solution due to plasma-water interaction has been shown in previous studies (41,43,44,48). The presence of these species is significant in the degradation of pollutants present in wastewater.…”

“…These species collectively have the potential to degrade the complex structure of these chemotherapy drugs. As the plasma-liquid interaction time increases, more and more reactive species are generated, as shown in supplementary material Table S2 (41)(42)(43)(44)48).…”

“…The species/radicals formed during air discharge in the NT-PPJ setup were identified by recording the optical emission spectra of air plasma using an optical fiber and spectrophotometers (maker StellarNet Inc. model no. EPP2000-UV (wavelength range 200 to 600 nm) and maker ASEQ instruments model UVH-1 (wavelength range 300 to 900 nm, spectra not shown in Figure 1(c))) (43,44).…”

“…The change in the physicochemical properties of methotrexate solution with increasing plasma treatment time is shown in Figure 2. These changes occur due to the dissolution of various short-lived and long-lived species in the methotrexate solution (41,43,44,48). As the plasma treatment time with methotrexate solution increases, a continuous decrease in pH and an increase in ORP, TDS, and EC are observed.…”