Induced Reactivity in Pollution-Control Plasmas through Real-Time Analysis in a Transportable FTICR Trap
Michel Héninger (Researcher-HDR), Joël Lemaire (Researcher), Essyllt Louarn (Associate Prof), Antoine Pallandre (Prof), Taous Abar (PhD Student), Hélène Mestdagh (Emeritus Prof)
Alumni: Sébastien Thomas (PhD 2014-18), Allan Lopes (PostDoc 2018)
The reactivity of non-thermal plasmas is complex, involving numerous species with a very broad energy spectrum. To compare experimental results with the modeling of various reactions involved, we chose to study the decomposition of acetone diluted in N2/O2 mixtures in the presence of a homogeneous discharge, specifically a photodischarged homogeneous discharge.
The plasma reactor is coupled with a compact FTICR mass spectrometer (BTrap) using chemical ionization, which performs real-time analyses of the various volatile organic compounds present. BTrap allows for the identification and quantification of acetone and its degradation by-products via plasma in real time, specifically every 10 seconds.
In this study, we demonstrated that the presence of oxygen significantly hampers acetone degradation and induces major changes in the reactions driven by the plasma, reflected in alterations to the distribution of by-products. While the primary products observed in gas mixtures without oxygen are nitrile compounds, they are replaced by oxygenated products, particularly formaldehyde, as well as nitrate and nitrite compounds including HNO2.

Simplified diagram illustrating the main reaction pathways leading to by-products of Volatile Organic Compounds (in bold) observed in a pure nitrogen plasma (black diagrams) and in an N2/O2 plasma (black, blue, and pink diagrams). [Thomas2022]