Improvement of energy efficiency for de colorization of organic dye by discharge inside bubble in water

Water purification by discharge inside bubble in water containing organic dye has been investigated. A tungsten wire is inserted into glass tube, which is immersed in the water. An aluminum film surrounds the glass tube as a grounded electrode. Oxygen and argon gases are injected into the glass tube to generate bubbles in the water. The pulsed high voltage generate d by a magnetic pulse compression circuit is applied to the tungsten wire to generate streamer discharge, which propagates into the bubble from the tip of the wire. Indigo carmine is employed as a specimen to evaluate decolorization efficiency. Energy efficiency for decolorization is improved by increasing number of discharges at same input energy and by decreasing pulse repetition rate. Ozone production efficiency increase s by decreasing humidity of the gas phase. Hydroxyl radical produced in the bubble mainly contribute to decolorize the solution in the case of argon injection. Ohmic loss decreases by increasing resistibility of the water by reducing surface area o f the grounded electrode and increasing gap length between t he electrodes.