Reactive species output of a plasma jet with a shielding gas device—combination of FTIR absorption spectroscopy and gas phase modelling

Abstract

In this work, a simple modelling approach combined with absorption spectroscopy of long living species generated by a cold atmospheric plasma jet yields insight into relevant gas phase chemistry. The reactive species output of the plasma jet is controlled using a shielding gas device. The shielding gas is varied using mixtures of oxygen and nitrogen at various humidity levels. Through the combination of Fourier transform infrared (FTIR) spectroscopy, computational fluid dynamics (CFD) simulations and zero dimensional kinetic modelling of the gas phase chemistry, insight into the underlying reaction mechanisms is gained. While the FTIR measurements yield absolute densities of ozone and nitrogen dioxide in the far field of the jet, the kinetic simulations give additional information on reaction pathways. The simulation is fitted to the experimentally obtained data, using the CFD simulations of the experimental setup to estimate the correct evaluation time for the kinetic simulation. It is shown that the ozone production of the plasma jet continuously rises with the oxygen content in the shielding gas, while it significantly drops as humidity is increased. The production of nitrogen dioxide reaches its maximum at about 30% oxygen content in the shielding gas. The underlying mechanisms are discussed based on the simulation results.

A Comparison of Floating-Electrode DBD and kINPen Jet: Plasma Parameters to Achieve Similar Growth Reduction in Colon Cancer Cells Under Standardized Conditions

“…For the kINPen plasma jet, this includes for example nitrite, nitrate, hydrogen peroxide, superoxide, hydroxyl radical, peroxynitrite, and singlet oxygen [72][73][74]. Plasma gas phase analysis suggests the presence of many others [75][76][77]. Yet, if organic target molecules and/or cells are not present at the site of species creation or deposition, short- lived species yield more stable products such as hydrogen peroxide or hypochlorous acid [73].…”

Influence of a plasma jet on the viability of Candida albicans

“…With increasing distance between the plasma jet and the sample, the flight-time of species in air increases from 0.3 to 0.9 ms, which allows reaction between the reactive species and particles in the post-plasma responsible for their transformation and decay before reaching the sample. According to SchidtBleker et al [20], the major reactive species that hit the samples are O 3 , NO 2 , NO and H 2 O 2 . According to Kutasi et al [21], the oxygen admixture to argon influences the electron energy distribution function (EEDF) by decreasing the average energy of electrons and reducing the high energy tail of the EEDF, as well as reducing metastable Ar states in the plasma.…”

A Direct Fourier Transform Infrared Spectroscopic Comparison of the Plasma- and Thermally-Driven Reaction of CO2 at Macor

“…There are few analytical studies on the chemistry taking place actually in the glow of non-thermal plasmas, and these largely employ emission spectroscopy [8][9][10] or the detection of a single species [11]. There are a number of studies on the downstream analysis of the exhaust from NTPs, see for example [12], but actual studies of the plasma glow with, for example, IR spectroscopy [13] or of the catalyst surface in contact with a plasma is only a relatively recent phenomenon [14][15][16][17][18]. It is critical, if the potential of NTP is to be realized, that the identities of the reactive species on and near the catalysts surface are revealed [19].…”