Oxidative processes occurring when pulsed high voltage discharges degrade phenol in aqueous solution

In this investigation, results obtained using a pulsed discharge for organic compound removal are presented. The degradation of phenol by a streamer corona discharge and spark discharge, the effects of hydrogen peroxide additive on removal efficiency, and photochemical oxidation by ultraviolet light from the discharge plasma channel were investigated. The intermediate products and final byproducts formed by the spark discharge were also studied. A preliminary study of the degradation mechanism inside and outside the plasma channel was carried out. It was found that the removal efficiency of organic contaminants in the aqueous solution was higher for the spark discharge than for the streamer corona discharge and was greatly influenced by the discharge type and additive. The energy efficiency was the highest (6.91 x 10(-3) mu mol/J) for the case with hydrogen peroxide injection and spark discharge. The main intermediate products produced by the spark discharge during the treatment process were hydroquinone, pyrocatechol, and p-benzoquinone. These intermediate products disappeared when the treatment time was increased.