Hydrogen, Oxygen, and Hydrogen Peroxide Formation in Aqueous Phase Pulsed Corona Electrical Discharge

High voltage electrical discharges in water are of increasing interest for the degradation of organic compounds and destruction of biological species. The present study reports measurements of the rates of molecular hydrogen, molecular oxygen, and hydrogen peroxide formation in a pulsed positive needle-plane corona-like electrical discharge in water. In experiments for various solution conductivities, applied voltages, and discharge powers, the ratio of the molar rate of production of hydrogen:hydrogen peroxide:oxygen was approximately 4:2:1. The highest observed rate of hydrogen production was 1.3 (mu)mol/s at discharge power of 37 W (or 0.25 g of H2/kW·h) at solution conductivity 50 (mu)S/cm. The G-value for hydrogen production was 0.17 molecule of H2/100 eV, falling in the range of that found in the radiation chemistry literature (~ 0-0.5 molecule of H2/100 eV, depending on scavenger concentration). A global reaction is proposed to add to existing kinetic models for the simulation of reactive species production in electrical discharge in water.