Interaction of Electrical Discharge with Water Solutions of Organic Compounds

This contribution presents results obtained from the investigation of the DC non-pulsed diaphragm discharge generated in water solutions of organic compounds. Organic dye Direct Red 79 was selected as a typical model of an organic molecule. Influence of experimental conditions and solution properties on the dye destruction by the discharge was studied. Especially characteristics such as solution conductivity, pH, presence of electrolyte and iron in the solution were observed. Decomposition of the dye was highly dependent on the applied voltage, both on the magnitude and polarity. The process efficiency was much higher in the negative discharge and it increased with the increasing power supply. Solution conductivity continually increased during the discharge due to the production of reactive species. The degradation process ran optimally at a particular conductivity value specific for each electrolyte used for the conductivity adjustment (600 μS·cm for the NaCl solution). Solution pH also changed during the discharge, but with an opposite effect in each discharge polarity. The addition of iron into the solution enhanced the dye decomposition.