Study on hydrogen peroxide generation by water surface discharge

Summary form only given. Water treatment using electrical discharge plasma, which can generate various physical and chemical processes, has attracted attention to reduce environment load and performance cost. However, there are many factors that influence these processes such as input voltage, pulse repetition rate, electrodes gap distance, water conductivity, pressure, temperature, pulse width and other plasma properties of discharge, which have not been well understood. We generated underwater discharge plasma and water surface discharge plasma using a pulsed power modulator, which is consisted of a semiconductor switch circuit and a magnetic pulse compression circuit. The pulse repetition rate of the modulator was changed from 50 to 1000 pulse per second (pps) and a point-to-plate electrode configuration was used. And we investigated the efficiency of hydrogen peroxide (H₂O₂) generation. Various chemical active species were generated when a discharge occurred. In this study we measured H₂O₂, which has relatively a long life time. TiSO₄ was added to the samples and H₂O₂ production was checked using a spectrophotometer. H₂O₂ generation efficiency decreased when pulse repetition rate increased in underwater discharge plasma. However, H₂O₂ generation efficiency did not decrease in water surface discharge plasma. Characteristic of streamer-like water surface discharge plasma was further investigated due to its high efficiency for water processing.