Pulsed electrical discharge in bubbled water for environmental applications

Summary form only given. Environmental applications of pulsed electrical discharge for water sterilization, decoloration, and decontamination are based on the generation of ozone, hydrogen peroxide, O, H and OH radicals and other chemically active species. This study investigates water purification and the production of active species by a pulsed electrical discharge in water in the presence of gas bubbles (oxygen, argon). 11-15 kV, ~5 mus pulses at a rate of 5-20 Hz are applied to horizontal parallel mesh electrodes in a reactor where water and gas bubbles pass vertically through the mesh electrodes. The organic dye, Rhodamine WT at an initial concentration of 200-400 ppb is used as a model to assess the effectiveness of the cleaning process for several reactor designs and experimental parameters. Significant reductions in the dye concentrations have been achieved, and the production of hydrogen peroxide and ozone has been investigated. The experiments reported here explore the effect of varying the power delivered to the system, the electrode configuration, oxygen gas flow rate, and solution flow rate on the decoloration process and on the production of hydrogen peroxide and ozone in the solution. Particular attention has been given to the dependence of the discharge characteristics on the size of the gas bubbles as compared the mesh size and the distance between the electrodes. This investigation also explores the importance of the background solution properties such as the initial pH and conductivity of the solution for the discharge process and the production of active species