| Previous research has demonstrated that a high voltage pulsed electrical discharge directly into water leads to the formation of reactive species such as hydrogen peroxide, hydroxyl radicals, and, when oxygen is present, ozone. This investigation involves analysis of the reactor performance under a wide range of operating conditions (including variation of added salt type, salt concentration, oxygen input, addition of activated carbon, ground electrode location, and ground electrode type) in order to optimize the hydrogen peroxide and ozone production and maximize phenol removal efficiency in the pulsed corona discharge reactor. Since significant quantities of hydrogen peroxide are produced, the role of Fenton's reactions in the pulsed corona reactor is studied in detail. Experimental data and computer simulations of the liquid phase reactions show the existence of optimal iron concentrations for the degradation of phenol. The addition of suspended activated carbon to the liquid solution is shown to enhance the phenol removal by adsorption of the organic molecules to the carbon and subsequent reaction of the organic molecules on the carbon surface. After the carbon particles were suspended in the solution treated by the pulsed corona, the physical properties of the carbon remain unchanged, and analysis of the carbon showed that little of the adsorbed phenol is present on the activated carbon after corona treatment of the solution. Computer modeling and sensitivity analysis has shown the importance of the surface reaction on the removal of phenol from the pulsed corona system.; Finally, a new reactor electrode configuration was used to remove phenol from the aqueous solution. A high voltage point electrode was submerged in the liquid phase while the planar ground electrode was placed in the gas above the liquid surface, resulting in a gas phase discharge in addition to the liquid phase discharge. As a result, high amounts of hydrogen peroxide and dissolved ozone were found in the aqueous solution. The greatest amount of dissolved ozone was seen when reticulated vitreous carbon was used as the ground electrode material. This new electrode configuration led to high phenol removal efficiencies under several different operating conditions. |
