Removal of 2-heptanone by dielectric barrier discharges - The effect of a catalyst support

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 1000 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 cm(3). 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 (.) 1(-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.