Formation of hydroxyl radicals and oxidation of toluene under corona discharge with water vapor as radical source

With water vapor as the radical source, hydroxyl radicals (·OH) of strong oxidation property were formed by corona discharge, which was directly detected by electron spin resonance (ESR) technology. These ·OH could efficiently degrade gaseous organic pollutants so as to reduce the toxicity of waste gas. The experimental result of toluene degradation under DC corona discharge showed that the degradation efficiency of toluene was nearly 100% in the medium of air containing saturated water vapor under the condition that interelectrode voltage was 20 kV, discharge current was 0.1 mA, reaction time was 120 s and initial concentration of toluene was 168 mg/m3, respetively. Seven intermediate products of toluene oxidation dissolving in liquid phase were also determined. The empolyment of environmental friendly ·OH provides a new approach for the removal of gas pollutants.