Chemistry in nanosecond plasmas in water. Issue 6 (16th January 2020)

• Record Type: Journal Article
• Authors: Chauvet, Laura; Nenbangkaeo, Chaiyasit; Grosse, Katharina; von Keudell, Achim
• Other Names: Benedikt Jan guestEditor.; Snyders Rony guestEditor.
• Is Part Of: Plasma processes and polymers. Volume 17:Issue 6(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-16
• Subjects: cavitation theory -- discharge in water -- global chemistry model -- H2O2 production -- nanosecond pulsed discharge; Plasma polymerization -- Periodicals; Plasma-enhanced chemical vapor deposition -- Periodicals; Plasma chemistry -- Periodicals
• DOI: 10.1002/ppap.201900192
• Languages: English
• ISSNs: 1612-8850

Abstract

Abstract: Discharges in liquids are the basis of a range of applications in electrochemistry, wastewater treatment, or plasma medicine. One advantage of discharges in water is their ability to produce radicals and molecules directly inside liquid with a high conversion efficiency. In this study, H2 O2 production in a 10 ns pulsed discharge in water is investigated. The dynamic of these discharges is based on plasma ignition directly inside liquid followed by the formation of a bubble that expands in time before it eventually collapses. This sequence can be well described by cavitation theory. H2 O2 is produced using different plasma conditions varying the treatment time, the pulse frequency between 1 and 100 Hz, and the applied voltage in a range from 15–30 kV. The resulting H2 O2 concentration is measured using absorption spectroscopy ex situ based on a colorimetry method. The results indicate that the main parameter controlling the H2 O2 production constitutes the applied voltage. The measured concentrations are compared with a global chemistry model simulating the chemistry involved during a single pulse using pressures and temperatures from the cavitation model. In addition, a global chemical equilibrium model for H2 O2 creation is evaluated as well. The models show a good agreement with the data. The energy efficiency for the production of H2 O2 reaches values up to 2 g/kWh. Abstract : Production of H2 O2 in a 10 ns pulsed discharge is investigated. The dynamic of this discharge can be described in two steps: the ignition in the liquid and the expansion of the bubble created subsequently; it is depicted thanks to the cavitation theory. The concentrations of H2 O2, measured by absorption spectroscopy combined with a colorimetric method, are compared to a global chemistry model and to a simple global chemical equilibrium model.