Decomposition of Organic Compounds in Water by Direct Contact of Gas Corona Discharge:  Influence of Discharge Conditions

Water purification experiments to decompose phenol, acetic acid, and Rhodamine B in water were conducted using a direct contact of gas corona discharge to the water surface. It was shown that O 2 was important in the gas phase for the degradation process, and the negative corona showed higher degradation rates than the positive corona. It was found that the organic contaminants can effectively be decomposed by the present method without pH adjustment. The experimental results indicated that there were optimized values in the O 2 concentration, the gas resident time above the water, and the cathode−anode gap. It was also indicated that the O 2 /CO 2 mixture showed a higher degradation rate than the O 2 /N 2 mixture for the gas phase. As the degradation mechanism, the uncharged short-lived radicals are considered to be important.