Dynamic analysis of absorbance behavior and peak shift of RONS in plasma-activated water by UV absorption spectroscopy: dependency on gas impurity, pulse polarity, and solution pH

Abstract

In this paper, we employ UV absorption spectroscopy to monitor the generation and permeation of reactive oxygen and nitrogen species (RONS) in plasma-activated water (PAW) to revealthe dynamic variation mechanism of RONS chemistry. Parameters including gas impurity, pulse polarity and solution pH value are varied to explore their effects on the absorbance behavior and peak shift of absorption spectra as well as the permeation distribution of RONS. Regarding the absorbance behavior, experimental results show that introducing air and N2 into He working gas would effectively improve RONS absorbance, proportions of about 0.2% air and 0.5% N2 would result in the maximum absorbance, while the addition of O2 would result in a significant decrease in RONS absorbance. Under positive polarity, the RONS absorbance is about 20% higher than that under negative polarity. Changing the solution pH from acidic to alkaline is beneficial in increasing RONS absorbance, indicating that alkaline solution could effectively promote RONS formation. Regarding the characteristic peak shift, different parameter conditions seriously affect the shift of the absorption peak toward low wavelength or high wavelength due to the change in the ratio of the concentration of each component of RONS in PAW. Furthermore, with respect to the permeation distribution of H2O2 and NO2 −, the results show that the addition of O2 would result in the fastest production rate of H2O2 and introducing air and N2 would generate the fastest rate of NO2 − production. Interestingly, the NO2 − permeation distribution displays a ‘columnar mode’ and a ‘filamentous mode’ under positive and negative polarity, respectively. An alkaline solution promotes the formation of NO2 − while having an obvious inhibiting effect on the NO2 − permeation; conversely, an acidic solution has a promotional effect on NO2 −. This study provides a new in-depth understanding of the dynamic evolutionary behavior of RONS in PAW, helping to reveal the network relationship between RONS, and assisting in the development of applications of PAW.

Diagnostic analysis of reactive species in plasma-activated water (PAW): current advances and outlooks

“…Amplex Red reagent reacts with liquid phase H 2 O 2 at a dose ratio of 1:1 under the catalysis of HRP to produce Resorufin with red fluorescence [42]. Liu et al [43] showed that the spatial and temporal color permeation distribution of H 2 O 2 in a cuvette in real time via the chemical fluorescent probes-Amplex ® Red reagent. The color shift occurs from yellow to blue after 3 min of PAW treatment with different working gases or with acid, neutral, and alkaline solutions, and it distributes over the entire cuvette with the extension of time.…”

Cascade N2 Reduction Process with DBD Plasma Oxidation and Electrocatalytic Reduction for Continuous Ammonia Synthesis

“…In order to determine the composition of the main products produced by DBD air plasma, the products are analyzed by optical emission spectroscopy (OES), in which different emission spectral lines reflect the types of active particles in the excited state . As shown in Figure d, the spectrum in the range of 200–800 nm is detected and recorded.…”

“…In order to determine the composition of the main products produced by DBD air plasma, the products are analyzed by optical emission spectroscopy (OES), in which different emission spectral lines reflect the types of active particles in the excited state. 32 As shown in Figure 4d, the spectrum in the range of 200−800 nm is detected and recorded. The dominant components of the spectrum were identified as the N 2 (C 3 ∏ U → B 3 ∏ g ) second positive system (SPS), the weak band of N 2 (B 3 ∏ g → A 3 ∑ u ) first positive system (FPS), and the N 2 + (B 2 ∑ U + → X 2 ∏ g + ) first negative system (FNS).…”

Effect of Gliding Arc Plasma Jet on the Mycobiota and Deoxynivalenol Levels in Naturally Contaminated Barley Grains

“…NTAPP is an eco-friendly technology generated by an ionized gas that produces reactive species from the gas phase of plasma, plasma–air interaction, or interaction with treated/activated substrates [ 2 ]. Reactive species are of great scientific interest due to the action of their active constituents in areas such as, medicine, dentistry, agriculture, environment, and food [ 1 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. The physicochemical reactions generated in plasma interaction with air create reactive species of oxygen and nitrogen (RONS), whose main constituents are nitrates (NO 3 ), nitrite (NO 2 ), peroxynitrite (ONOO − ), hydrogen peroxide (H 2 O 2 ), hydroxyl (OH), oxygen (O 2 ), superoxide (O 2 ), and ozone (O 3 ) [ 2 , 3 , 5 , 10 ].…”

“…Reactive species are of great scientific interest due to the action of their active constituents in areas such as, medicine, dentistry, agriculture, environment, and food [ 1 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. The physicochemical reactions generated in plasma interaction with air create reactive species of oxygen and nitrogen (RONS), whose main constituents are nitrates (NO 3 ), nitrite (NO 2 ), peroxynitrite (ONOO − ), hydrogen peroxide (H 2 O 2 ), hydroxyl (OH), oxygen (O 2 ), superoxide (O 2 ), and ozone (O 3 ) [ 2 , 3 , 5 , 10 ]. These plasmas are generally generated as plasma jets (PJ) and may be applied directly or indirectly [ 1 , 8 , 11 , 12 , 13 ].…”