Application of ultraviolet photooxidation to remove organic pollutants in the gas phase

The photooxidation of volatile organic compounds (VOCs) such as benzene, toluene, and cis-1, 2-dichloroethylene (DCE) using low-pressure mercury UV lamp as the irradiation source is described. The kinetics of the gas phase photooxidation was evaluated by varying different conditions, such as initial concentrations of the VOCs, intensity of radiation, humidity, temperature and reaction medium. The results showed that the low-pressure mercury UV lamp with relatively low radiant intensity is capable of destroying various types of organic pollutants. The photooxidation rates increased with the presence of moisture and the chloride radical in the mixture, and the effect was more pronounced for compounds with reactive hydrogen. The results indicate that the photooxidation process is ideal for on-site non-combustion destruction of different types of organics present in the off-gas resulting from treatment technologies such as soil-vapor extraction and air stripping. (C) 2000 Elsevier Science B.V. All rights reserved.