Industrial & Engineering Chemistry Research, Vol.39, No.11, 4408-4414, 2000
A pulseless corona-discharge process for the oxidation of organic compounds in water
Ozone is widely used to deactivate microorganisms and remove organic contaminants in water industries. However, interest also exists in using radical species, which are stronger oxidants than ozone, in such processes. One means of producing radical species is by corona discharge. This work investigates the use of a novel pulseless corona-discharge system for the removal of organic substances. The method combines corona discharge with electrohydrodynamic spraying of oxygen, forming microbubbles. Experimental results show that pulseless corona discharge effectively removes organics, such as phenol and methylene blue, in deionized water. The corona-discharge method is demonstrated to be comparable to the direct use of ozone at a high applied voltage. The results also show that a minimum applied voltage exists for an effective operation of the corona-discharge method. In this work, the minimum applied voltage is approximately 4-4.5 kV over a 3-cm distance between the electrodes. The kinetic rate of phenol degradation in the reactor is modeled. Modeling results show that the dominant species of the pulseless corona-discharge reactor are hydroxyl radical and aqueous electron. Several radical species produced in the pulseless corona-discharge process are identified experimentally. The major species are hydroxyl radical, atomic hydrogen species, and ozone.