Production and transport of plasma-generated hydrogen peroxide from gas to liquid

Abstract

In this work, the transport of hydroxyl radicals and hydrogen peroxide from a humid atmospheric pressure plasma jet into plasma-treated liquids is analysed. The concentration of H2O2 was measured by...

Nitrogen fixation and H2O2 production by an atmospheric pressure plasma jet operated in He–H20–N2–O2 gas mixtures

“…For short-lived species such as OH, the dependence of concentration on the distance was found to be an exponential decay in a previous publication of this plasma jet-liquid configuration. [37] The three species studied here are known to be long-lived species; [51] hence, the weak decreasing trend observed is plausible.…”

“…The shorter residence time (1.2 ms) at a gas flow rate of 2 slm is still sufficient for the production of the reactive species, and a constant H O 2 2 density in the gas phase was found in the simulations for all gas flow rates studied. [37] Likely, this is also the case for other longlived species such as NH 3 and NO 2 − , as these timescales are also in the millisecond range. [21,31,52] Thus, as the gas flow rate doubles, so does the amount of species reaching the liquid surface.…”

“…This agrees well with the trend observed in our previous publication for a He+H O 2 plasma. [37] At this low duty cycle, an accumulation of H O 2 2 was observed, where OH is generated during the plasma-on time and recombined to H O 2 2 during the plasma-off time. This is also the case when N 2 is added to the system.…”

“…One example of voltage waveforms during power modulation is shown in the Supporting Information and the used frequencies and duty cycles with the corresponding number of pulses per residence can be found in an earlier publication. [37] In unmodulated cases, power measurements were performed as described by Golda et al [38] An oscilloscope (Teledyne LeCroy HDO6104A, 10 GS s −1 ) is used for detecting the voltage and current signals. The voltage was measured using a miniaturised voltage probe placed behind the powered electrode.…”

“…[34] Nevertheless, with further development of the COST reference plasma jet by using a capillary that keeps the plasma behaviour identical, [35] higher plasma powers and higher reactive admixtures can be used, and competitive concentrations of, for example, H O 2 2 can be measured. [36,37] Thus, this wellcharacterised plasma source can also be used to study the concentration of RONS in plasma-treated liquid and for comparison with other plasma sources.…”