Pulsed Elektrical Discharge in Bubbled Water for Environmental Applications

Summary form only given. Pulsed electrical discharges are frequently used for generating ozone, hydrogen peroxide, O, H and OH radicals and other chemically active species utilized for water sterilization, decoloration, and decontamination. This study investigates radical production and water purification by electrical discharges in water in the presence of oxygen bubbles. The organic dye, Rhodomine WT at an initial concentration of 200-400 ppb is used as a model compound to access the effectiveness of the cleaning process for several reactor designs and experimental parameters. The rhodomine concentration is determined using fluorescence spectroscopy. Significant reductions in the dye concentrations have been achieved by applying 12-16 kV pulses at a rate of up to 80 Hz to a reactor with horizontal parallel mesh electrodes, 5 mm apart and water flowing and bubbles passing vertically through the electrodes. Several other reactor designs have been investigated. The experiments reported here explore the effect of varying the power delivered to the system, the electrode configuration, the oxygen gas flow rate and solution flow rate, and the initial pH and conductivity of the solution on the decoloration process and on the production of hydrogen peroxide and ozone in the solution. Mechanisms are discussed that are responsible for the importance of the background solution properties such as pH and conductivity on the effectiveness of the production of active species.