Study of Wastewater Treatment by OH Radicals Using DC and Pulsed Corona Discharge over Water

摘要

Water treatment by OH radicals is studied using dc and pulsed corona discharge over water at atmospheric pressure and reduced pressure. In particular, we pay attention to the influence of discharge configuration on the efficiency of wastewater treatment. Experiment is carried out in N_2 to clarify the contribution of OH radicals. Needle-cylinder electrodes are designed expecting the efficient generation of OH radicals close to the water surface. N,N-dimethyl-p-nitrosoaniline (RNO) solution is used as a persistent test pollutant. The results strongly suggest that OH radical production close to the water surface is a key factor for efficient wastewater treatment. The use of pulsed discharge at reduced pressure is effective in improving RNO reduction efficiency because of the rapid diffusion of OH radicals to the water surface.