The transportation of plasma-generated species through a liquid environment is a key step within the plasma-driven biocatalysis process, but is also of great importance for other systems with plasma-liquid interfaces. The aim of this study is to explore the transportation processes and lifetime of plasma-generated species in an aqueous solution. Therefore, a combination of experimental methods, reactive molecular dynamics simulations, and reaction-diffusion modelling was used. Experimentally, an atmospheric pressure plasma jet was used to treat an aqueous sample. Convective transport was visualized by particle image velocimetry in the plasma-treated water. Chemiluminescence measurements of OH were conducted by the use of luminol and 2D-UV-absorption spectroscopy was used to detect H2O2 in the plasma-treated water. The strength of convective transport was found to decrease with the gas flow rate through the jet, and at low gas flows, an effective diffusion coefficient for H2O2 could be calculated. OH was mainly present at the liquid surface under all treatments investigated. The reactive molecular dynamics simulations form the basic model of an ideal system, where all transportation is purely diffusion-driven, and molecular diffusion coefficients can be calculated. The results of the MD simulations were compared with the experimental studies to gain a deeper understanding of the differences between the ideal and the real system. To bridge the gap between the time scales of the MD simulations and the experiments, a kinetic model was used to understand the spatio-temporal changes and the influence of transport mechanisms and reaction chemistry. For low flow rate cases good agreement between experimental measurements and kinetic modelling could be obtained when the experimentally measured effective diffusion coefficient was used as input to the model. The differences in the H2O2 concentration profiles in the liquid when using the molecular diffusion coefficient derived from MD and the effective diffusion coefficient from the experimental measurements are highlighted.
Field | Value |
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Authors | |
Release Date | 2025-01-21 |
Identifier | e474bf36-73f8-4cf7-974b-cb5638c68bfa |
Permanent Identifier (URI) | |
Is supplementing | |
Plasma Source Name | |
Plasma Source Application | |
Plasma Source Specification | |
Plasma Source Properties | Two stainless steel electrodes with capillary (borosilicate, wall thickness 0.2mm) in between. Dimension of plasma: width: 1mm, length: 40mm, height: 1mm, Volume: 40mm³. Distance between electrodes: 1.4mm. Distance between electrode (plasma) end to capillary exit: 10mm. Sinusoidal waveform at 13.56 MHz with voltages (rms) between 150 and 700V. Plasma powers of up to 10W. Gas composition varies. |
Language | English (United Kingdom) |
License | |
Plasma Medium Name | |
Plasma Medium Properties | Flow rate: 0,25 to 2 slm, humidity admixtures: 0 - 6400ppm (0-100% of gas flow through ice-cooled bubbler) |
Plasma Medium Procedure | Cooling of the bubbler 1h before measurements with 900mL ice cubes and 400mL fridge cooled water. |
Plasma Target Name | |
Contact Name | Hanna-Friederike Poggemann, Steffen Schüttler, Anna Lena Schöne |
Plasma Target Properties | 3 mL liquid volume in UV cuvette, adjustment of capillary to a distance of 14mm from liquid surface |
Plasma Diagnostic Properties | Plasma experiments: Chemiluminescence using luminol, particle imaging velocimetry using 55µm polyamide particles, UV absorption of H2O2 in the wavelength range from 237 nm to 271 nm;
MD Simulations: ReaxFF MD Simulations with LAMMPS Molecular Dynamics Simulator, simulation details can be found in the provided input files;
Kinetic modelling: Mass transport with reaction kinetics - Solving reaction-diffusion equation |
Public Access Level | Public |
Plasma Diagnostic Name | |
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Data and Resources
- figure_02_a_0,5slmtxt
Plot data of the chemiluminescence signal of luminol shown as 2D map at a...
Download - figure_02_a_1,0slmtxt
Plot data of the chemiluminescence signal of luminol shown as 2D map at a...
Download - figure_02_a_2,0slmtxt
Plot data of the chemiluminescence signal of luminol shown as 2D map at a...
Download - figure_02_b_0,5slmzip
Plot data of the PIV images displayed as a 2D map at a gas flow rate of 0....
Download - figure_02_b_1,0slmzip
Plot data of the PIV images displayed as a 2D map at a gas flow rate of 1....
Download - figure_02_b_2,0slmzip
Plot data of the PIV images displayed as a 2D map at a gas flow rate of 2....
Download - figure_03_0,5slmtxt
Plot data of the UV absorption of H2O2 at various depths at a gas flow rate...
Download - figure_03_1,0slmtxt
Plot data of the UV absorption of H2O2 at various depths at a gas flow rate...
Download - figure_03_2,0slmtxt
Plot data of the UV absorption of H2O2 at various depths at a gas flow rate...
Download - figure_04_a_total_absorbance_meantxt
Plot data of the UV absorption of H2O2 during a long treatment of 30 minutes...
Download - figure_04_a_total_absorbance_maxtxt
Plot data of the UV absorption of H2O2 during a long treatment of 30 minutes...
Download - figure_04_a_total_absorbance_mintxt
Plot data of the UV absorption of H2O2 during a long treatment of 30 minutes...
Download - MD simulation files for figure 05 and 06zip
The folder contains the basic files to reproduce the MD simulation of the...
Download - MD simulation files for figure 07zip
The folder contains the basic files to reproduce the MD simulation of the...
Download - figure_10_experimenttxt
Experimentally measured and normalised H2O2 concentration over time at...
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