Characteristics of active species formation by pulsed high voltage discharge in water

The characteristic of active species formation in aqueous phase is investig ated by applying a high voltage pulse to needle-plate electrode configurati on. Radicals (. OH, . O, . H) were detected by analyzing emission spectra f rom the discharge channel. It is found that the radical formation is slight ly delayed (similar to 1 mu s in the order of magnitude, depending on risin g time of the applied pulse) from the peak of the applied voltage. Formatio n of radicals is also influenced by pulse wave shape such as half width and peak voltage, and oxygen gas bubbling into the discharge region. Hydrogen peroxide is formed by the pulsed discharge where the formation rate is larg er in the case with oxygen gas bubbling than that of no bubbling.