Generation of chemically active species by electrical discharges in water

Pulse positive streamer corona discharges in water solution with a differen t conductivity have been investigated in reactors with the needle-plate and coaxial electrode geometry. A special composite anode was used in the coax ial geometry. With such an anode hundreds of streamers were generated at ea ch voltage pulse. Production of H, O and OH radicals by the discharge was p roved by emission spectroscopy and formation of H2O2 and degradation of phe nol was demonstrated by chemical methods. Assuming that the broadening of t he H alpha line profile was caused by the dynamic Stark effect, plasma with an electron density over 10(18) cm(-3) was generated during the initial ph ase of voltage pulse in the both reactors in spite of the very different el ectrode geometry and wave-forms of voltage pulses.. Production of OH radica ls was most effective at solution conductivity below 100 mu S cm(-1).