Pulsed-discharge Purification of Water Containing Non-degradable Hazardous Substances

Abstract

The decomposition characteristics of phenol in an aqueous solution by the exposure of a pulsed-discharge plasma are investigated for different electrode configuration, applied voltage, and the humidity and composition of a background gas. It is likely that OH radicals are responsible for the decomposition of phenol in the solution for all kind of background gases. In pure O2, the decomposition rate of phenol increases due to the generation of O and O3, and in pure N2, OH radicals, produced by N2 excited in metastable state, contribute to the phenol decomposition. In N2-O2, the decomposition rate of phenol stays lower values, since NOx, produced by the pulsed plasma, reduces O3 concentration and the production of the NOx inhibits O3 production. In Ar-O2, the decomposition rate of phenol rises with an increase in the mixture ratio of Ar. It is likely that excited Ar atoms are responsible for the decomposition of phenol in the solution at higher mixture ratio of Ar. Further, no significant difference in the decomposition rate is found between the pulsed discharge and a DC corona discharge.