Summary: 2‐heptanone is representative of a class of odorous molecules. Recent studies have shown that by adding a catalyst to a dielectric barrier discharge (DBD) plasma, the elimination of 90% of this molecule can be achieved with low consumption of electric energy, at room temperature, for concentrations below 1 000 ppm. In the presented work, the removal of the ketone by DBD, both in dry air and within a slice of a honeycomb monolith of cordierite without a catalyst, was studied. In both experiments, the discharge was operated in a plane‐to‐plane geometry with a discharge volume of 10 cm3. A high voltage, bipolar pulse generator (40 kV max, 1–140 Hz frequency range) was used. In dry air, it was found that 2‐heptanone is almost totally removed (>95%) for a specific deposited energy of about 500 J · l−1, but this elimination is less effective in the porous cordierite reactor (80%) for the same energy. This effect is explained by the very different spatial distribution of the plasma within the discharge volume, as seen using a CCD camera. Moreover, the adsorption‐desorption equilibrium of the molecule at the surface of the material is greatly influenced by the discharge.
Low-current (∼250 mA), high-voltage (∼700 V), dc discharges are observed to operate in air at atmospheric pressure when a closed loop is included for current regulation on the power supply. A dynamic process might control the discharge steadiness more efficiently than the conventional stability criterion that compares the slope of the static volt-ampere characteristic to the value of the external ballast resistor. To check the validity of the inferred stabilization process, a typical 4.7 cm long plasma filament operates in ambient air. Optical and electrical diagnostics are performed to investigate the discharge properties. Measurements then reveal most typical features of an actual arc discharge in air. Consequently, a numerical simulation based on a time-dependent Elenbaas-Heller equation allows calculation of the time-evolution of the plasma in the discharge. Finally, electron density measurements using a specific microwave absorption device confirm the high rate of ionization of the plasma: almost two orders of magnitude higher than for a typical glow discharge in free air.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.