Removal of phenol in water by pulsed high voltage discharge

Abstract

Summary form only given. Recently, environmental pollution has been become a global problem. The development of advanced oxidation processes (AOP) for treatment of hazardous chemical contaminated wastes has grown rapidly. Of all these treatments, pulsed high voltage electrical discharge that produce non-thermal plasma, has been studied for degrading small organic species in wastewater. The discharge in water and aqueous solutions are efficient in the creation of a variety of effects as shock waves, ultraviolet radiation, high electric fields and, especially formation of chemically active species acting on biological cells and chemical compounds dissolved in water. Advantages of the pulsed discharge treatment are simultaneous removal of several pollutants, operation at ambient temperature and pressure, high destruction efficiency and no selection for contamination. But it has not been reported to compare the effect of different electrode type reactor and discharge energy on removal. In this study, we investigated phenol removal efficiency with pulsed discharge in water with various electrode type reactors (rod-rod, rod-plate and wire-cylinder) and discharge energy. The results show that, of three reactor types, the removal efficiency with wire-cylinder reactor was the highest, the removal efficiency with rod-rod and rod-plate reactor were almost the same. As for wire-cylinder reactor, removal efficiency does not strong depend on anode wire length and discharge voltage in our experimental conditions. However, it is improved by decreasing arc discharge by changing storage energy of the capacitance. In addition, effect of hydrogen peroxide on removal rate was also studied. When hydrogen peroxide 50 ppm or 200 ppm was added into the reactor, the phenol degradation rate becomes dramatically higher.